Savage///Chats

I'm considering building something like this as a quick / cheap way to get people familiar with Z80 programming.

Z80 Emulator for Raspberry Pi Pico and other RP2040 based MCU boards (https://github.com/djbottrill/rp2040_z80_emulator)

It could run on this $4.00 Raspberry Pi Pico RP2040 (https://www.adafruit.com/product/4864?gad_source=1&gad_campaignid=21079227318&gbraid=0AAAAADx9JvRA4ZaQ1qTvuAsCId632A5MX&gclid=EAIaIQobChMIrMD42v7nkQMVuzIIBR3--ynEEAQYBSABEgInmvD_BwE) from Adafruit.

That sounds pretty good. I am using RUNCPM (https://github.com/guidol70/RunCPM_RPi_Pico) on my PicoCalc (https://forum.clockworkpi.com/t/runcpm-for-picocalc/20459 (https://forum.clockworkpi.com/t/runcpm-for-picocalc/20459).) On the PicoCalc, it takes the normally 40-column screen and displays 80 columns on it - takes a bit of practice to get used to the squished characters, but that would not be any trouble with using a terminal emulator (minicom - https://en.wikipedia.org/wiki/Minicom (https://en.wikipedia.org/wiki/Minicom), or TeraTerm - https://en.wikipedia.org/wiki/Tera_Term (https://en.wikipedia.org/wiki/Tera_Term)) on just a plain Pico.

I was amazed at the amount of software included with RUNCPM. I have just started going over the drives (yes, on the SD card image - https://obsolescence.wixsite.com/obsolescence/multicomp-fpga-cpm-demo-disk there are five hard disk images (with may USER areas each,) with a huge number of programs. I mentioned to Marilyn that this would have been the collection of an extremely rich professional programmer back in the '70s.

You need to add an SD card socket (https://www.amazon.com/DIYables-Adapter-Arduino-ESP8266-Raspberry/dp/B0BXKLNN2L (https://www.amazon.com/DIYables-Adapter-Arduino-ESP8266-Raspberry/dp/B0BXKLNN2L), but that, with a breadboard and some hookup wires, would provide an entire usable Z-80 CP/M system. Looks like your suggestion; it would be about the cheapest you can get.

I've been taking a closer look at the version that you posted. I really like the V. 2.2 version implementing the telnet server over WiFi. That would be really cool, plus it implies that a WiFi network connection could be added to allow CP-Net (http://cpmarchives.classiccmp.org/cpm/Miscellany/cpnet.html) network access to other servers, and simple web pages.

I do like the N8VEM collection of disks for RUNCPM - that is a serious collection. I'm thinking that some/all of those programs may be able to be installed for that David Bottrill Z-80 emulator that you mentioned. I noticed that the A: drive on David's Git page is a hard drive (8 Megabytes,) but I could not see what all was on that image. Also, I have not seen how to add other drives, but you may be able to take some of the stuff from the N8VEM disks and copy them over.

Also, the newest version of RUNCPM for the PicoCalc (https://github.com/theflynn49/picocalc_runCPM/releases/tag/v1.5) allows a Pico 2(W) to run CP/M at 200MHz on the Pico - that translates to a 32Mhz(!) Z-80 clone. :o I'm almost afraid to try Ladders on the PicoCalc. ;D


** Edited to fix link to the newest version of RunCPM.

I was thinking this would provide an easier path to messing around with the Z80 using modern hardware. While I don't have the time to explore it at the moment, I would be happy to fund such an endeavor, should someone want to pursue it. It could then be duplicated to open the door to others as well.

Quote from: Chris Savage on Dec 31, 2025, 09:05 AMI'm considering building something like this as a quick / cheap way to get people familiar with Z80 programming.

Z80 Emulator for Raspberry Pi Pico and other RP2040 based MCU boards (https://github.com/djbottrill/rp2040_z80_emulator)

It could run on this $4.00 Raspberry Pi Pico RP2040 (https://www.adafruit.com/product/4864?gad_source=1&gad_campaignid=21079227318&gbraid=0AAAAADx9JvRA4ZaQ1qTvuAsCId632A5MX&gclid=EAIaIQobChMIrMD42v7nkQMVuzIIBR3--ynEEAQYBSABEgInmvD_BwE) from Adafruit.

If the ZX80/81 are Z80 based, in theory this could be modicied to work on the ZX80/81.

Quote from: JKnightandKARR on Jan 01, 2026, 08:14 PMIf the ZX80/81 are Z80 based, in theory this could be modicied to work on the ZX80/81.

Yes, and there are several projects that do this. @ikjordan has a GitHub page (https://github.com/ikjordan/picozx81?tab=readme-ov-file) with one. His (hers?) works on several platforms, one of which is less than $25 from Pimoroni (https://www.pishop.us/product/pimoroni-pico-vga-demo-base (https://www.pishop.us/product/pimoroni-pico-vga-demo-base).)

But, if you let go of the ZX-81 format, and just use a serial terminal on your PC, you can get full Z-80 experience from just the Pico, a breadboard, a micro-USB cable and some hook-up wires (and optionally an SD card socket.) Of course, you won't get the single-key BASIC, the low-rez graphics nor the ZX gaming experiences with these projects. You also won't have a true Z-80 hardware system - but if that is not so important, these projects will be cheaper.

I found another GitHub project that emulates the Z80 on the Pico https://github.com/udo-munk/RP2xxx-GEEK-80 (https://github.com/udo-munk/RP2xxx-GEEK-80) It uses a WaveshareRP2040-GEEK such as https://www.waveshare.com/rp2040-geek.htm (https://www.waveshare.com/rp2040-geek.htm). It runs for $9.00 but it looks easier to do since the SD card reader and a (very small) LCD are included and it plugs into an USB port.

You guys are coming up with some great ideas. I have a lot of data to go over to decide what to build for this. While I personally, am interested in my hardware system, I am looking to get others interested, and therefore would like to build / support an emulator-based system that is inexpensive.

Quote from: MicroNut on Jan 20, 2026, 09:38 AMI found another GitHub project that emulates the Z80 on the Pico https://github.com/udo-munk/RP2xxx-GEEK-80 (https://github.com/udo-munk/RP2xxx-GEEK-80) It uses a WaveshareRP2040-GEEK such as https://www.waveshare.com/rp2040-geek.htm (https://www.waveshare.com/rp2040-geek.htm). It runs for $9.00 but it looks easier to do since the SD card reader and a (very small) LCD are included and it plugs into an USB port.

Have you ordered/received one of those RP2040GEEK devices, yet?

I checked, and the LCD has a ST7789 controller, for which PicoMite BASIC already has drivers built-in. In addition, the schematic shows the pins for the SD card (https://files.waveshare.com/wiki/RP2040-GEEK/RP2040-GEEK-Schematic.pdf bottom of page,) and so it looks like it will work for RunCPM. Add a cheapie SD card with the files from Grant Searle's Multicomp CP/M machine (https://obsolescence.wixsite.com/obsolescence/multicomp-fpga-cpm-demo-disk (https://obsolescence.wixsite.com/obsolescence/multicomp-fpga-cpm-demo-disk), click on the "Download Tool Set" button on the left) and you have a $9 (plus ~$15 shipping) pocket super CP/M computer - use your regular PC/notebook/tablet as the terminal.

I have added three of these to my Waveshare cart, and tomorrow when I get my allowance they will be ordered. The only bad part is that the shipping to the U.S. can take 20-30 days. Also, that $15 shipping price is supposed to cover up to 2 kilograms - and at 0.045 kg per device we can order over 44 before the shipping goes up!  ;D

Also, if you only want one, Amazon has them for $15.35 (two-day free delivery with Prime https://www.amazon.com/waveshare-Development-Board-Microcontroller-Downloader/dp/B0CGLBLQ43) This is only 35 cents higher than the shipping alone from Waveshare. Maybe I'll order one from Amazon, just to get it quicker.

Quote from: MicroNut on Jan 20, 2026, 09:38 AMI found another GitHub project that emulates the Z80 on the Pico https://github.com/udo-munk/RP2xxx-GEEK-80 (https://github.com/udo-munk/RP2xxx-GEEK-80) It uses a WaveshareRP2040-GEEK such as https://www.waveshare.com/rp2040-geek.htm (https://www.waveshare.com/rp2040-geek.htm). It runs for $9.00 but it looks easier to do since the SD card reader and a (very small) LCD are included and it plugs into an USB port.

I took another look at that project of putting Udo Munk's Z-80 emulator onto the RP2040-GEEK device. Wow! With switching to the RP2350-GEEK you can get multi-user MP/M running with two users. Also, you can set up the onboard LCD simulating the Cromemco Dazzler
(https://github.com/udo-munk/RP2xxx-GEEK-80/blob/main/resources/micro80.jpg?raw=true)
 I remember, almost salivating over the Dazzler at the Computer Land store near my house. It was in a Polymorphic Poly 88 (https://oldcomputers.net/poly-88.html (https://oldcomputers.net/poly-88.html),) and was one of the coolest things that I had seen. The display was running the KSCOPE demo:
and I loved it.

I now have one of the RP2350-GEEK devices, from Amazon, on its way - should be here Friday. I also added two more of them to my WaveShare cart. I'm going to have to trim back some of the RP2040-GEEKs from the cart (unless I get rich by tomorrow.  ;) ) Although, maybe I'll hold off on the WaveShare order until I after Friday, when I get the RP2350-GEEK. That way I can test them out and make sure that they will do what I want.

This thread was marked as a "breadcrumb" in case you, or I or anyone else needs to find this again.

No I don't have one. I had a quick break at work and decided to look up Z80 emulation on a pico using ChatGPT and the Waveshare link came up. It looked cool so I posted it. Let me know how it works and I'll probably order one from Amazon.

Quote from: MicroNut on Jan 20, 2026, 06:46 PMNo I don't have one. I had a quick break at work and decided to look up Z80 emulation on a pico using ChatGPT and the Waveshare link came up. It looked cool so I posted it. Let me know how it works and I'll probably order one from Amazon.

Yeah, twenty to thirty days is a pretty long time to wait. If I have one to play with, I can wait that long for additional units that are much lower cost.

Isn't the Rasp Pi Pico the RP2040? If so I got an extra when I was starting the PicoMite. I gots too many projects need to start kne n get done...

Quote from: JKnightandKARR on Jan 21, 2026, 05:54 PMIsn't the Rasp Pi Pico the RP2040? If so I got an extra when I was starting the PicoMite. I gots too many projects need to start kne n get done...

Yes, the Raspberry Pi RP2040 is a microcontroller chip from the Raspberry Pi Foundation (https://www.raspberrypi.com/products/rp2040/.)
(https://assets.raspberrypi.com/static/chips-a126ba53c50bb160d65210696edf8ad9.png)

It is the brains behind the RP2040-GEEK, and the Raspberry Pi Pico, the PicoCalc and many other devices. The RP2040-GEEK takes that controller, adds the LCD, RAM, Flash Memory and a case and makes a pretty cool device for playing working.

I thought so.

Quote from: granz on Jan 21, 2026, 06:19 PMThe RP2040-GEEK takes that controller, adds the LCD, RAM, Flash Memory and a case and makes a pretty cool device for playing working.

I fixed it for ya. Lol

Quote from: JKnightandKARR on Jan 21, 2026, 07:01 PMI thought so.

Quote from: granz on Jan 21, 2026, 06:19 PMThe RP2040-GEEK takes that controller, adds the LCD, RAM, Flash Memory and a case and makes a pretty cool device for playing working.

I fixed it for ya. Lol

Hah, nice. I guess that fits better now that I'm retired.  8)

Gentlemen,

Would this setup allow for writing assembly code and viewing results? I'm going to be placing some orders this weekend and wanted to get what would be needed to realize a Z80 development system. I need to check the other thread as well, since I thought there was hardware I needed to order for that as well.

Quote from: Chris Savage on Jan 22, 2026, 01:54 PMGentlemen,

Would this setup allow for writing assembly code and viewing results? I'm going to be placing some orders this weekend and wanted to get what would be needed to realize a Z80 development system. I need to check the other thread as well, since I thought there was hardware I needed to order for that as well.

As far as emulation goes only exp I have is with ROMs for games.. This kinda stuff idk..

Marilyn brought a package in and touched my arm with it. I about jumped out of my skin - apparently I had fallen asleep at my desk.  :o
(https://files.granzeier.com/Downloads/SavageCircuits/RP2350-GEEK%20New.jpeg)

The newest version of PicoMite (Ver 6.01.00 https://geoffg.net/Downloads/picomite/PicoMite_Firmware.zip) installed very quickly, and easily. That "Boot" button on the side is a pleasure to work with.

Notice the huge 16MB A: drive:
(https://files.granzeier.com/Downloads/SavageCircuits/RP2350-GEEK%20Screen.jpeg)

It was not a big trouble to get the SD Card working. The schematic shows the Chip Select pin as connected to GP23, but PicoMite won't use that - that pin is not available on a regular Pico. But there are a couple other pins that were not used, so I tried GP21, and it worked just fine:
(https://files.granzeier.com/Downloads/SavageCircuits/RP2350-GEEK%20Card.jpg)
OPTION SDCARD GP21, GP18, GP19, GP20

With the SD Card connections working in PicoMite, it looks good for RunCPM. I'll work on that in a little while.

I am having troubles with the LCD, the schematic shows a MOSI connected, but no MISO. PicoMite BASIC is supposed to work on LCDs without a frame buffer (I.E. no need for data from the LCD, or rather the slave, thus no need for MISO.) So far, I have not been able to find the way to set up PicoMite to use the LCD, yet! :P I'll get it, but time for dinner with my favorite girl, a movie, and then hit the sack (apparently I'm more tired than I thought. ::) )

Quote from: granz on Jan 22, 2026, 06:10 PMMarilyn brought a package in and touched my arm with it. I about jumped out of my skin - apparently I had fallen asleep at my desk.  :o
(https://files.granzeier.com/Downloads/SavageCircuits/RP2350-GEEK%20New.jpeg)

The newest version of PicoMite (Ver 6.01.00 https://geoffg.net/Downloads/picomite/PicoMite_Firmware.zip) installed very quickly, and easily. That "Boot" button on the side is a pleasure to work with.

Notice the huge 16MB A: drive:
(https://files.granzeier.com/Downloads/SavageCircuits/RP2350-GEEK%20Screen.jpeg)

It was not a big trouble to get the SD Card working. The schematic shows the Chip Select pin as connected to GP23, but PicoMite won't use that - that pin is not available on a regular Pico. But there are a couple other pins that were not used, so I tried GP21, and it worked just fine:
(https://files.granzeier.com/Downloads/SavageCircuits/RP2350-GEEK%20Card.jpg)
OPTION SDCARD GP21, GP18, GP19, GP20

With the SD Card connections working in PicoMite, it looks good for RunCPM. I'll work on that in a little while.

I am having troubles with the LCD, the schematic shows a MOSI connected, but no MISO. PicoMite BASIC is supposed to work on LCDs without a frame buffer (I.E. no need for data from the LCD, or rather the slave, thus no need for MISO.) So far, I have not been able to find the way to set up PicoMite to use the LCD, yet! :P I'll get it, but time for dinner with my favorite girl, a movie, and then hit the sack (apparently I'm more tired than I thought. ::) )

I wonder what the changes are? Still hoping I can do DTMF with it..

EDIT: Looks like:
' To play DTMF '1' (697Hz + 1209Hz)
PLAY TONE 697, 1209, 100 ' Play for 100ms
Will do it. Have to check!

Quote from: JKnightandKARR on Jan 22, 2026, 06:43 PMI wonder what the changes are? Still hoping I can do DTMF with it..

EDIT: Looks like:
' To play DTMF '1' (697Hz + 1209Hz)
PLAY TONE 697, 1209, 100 ' Play for 100ms
Will do it. Have to check!

Available GPIO pins are: GP2, 3, 4, 5, 28 & 29. At least those are the ones brought out to the headers on the side. Using OPTION AUDIO, you can choose PWM1 (GP2 & 3) or PWM2 (GP4 & 5,) those are brought out to the headers. You would need to add the filter hardware on page 48 of the 6.01.00 manual - I would use the first one, just four 22nF caps, and four 680Ω resistors (although running it into an amplifier may do it without the filter.) Also, the example that you gave will produce the two different frequencies on the two channels (left & right.) So you will need to combine them (electrically, or audibly) to generate the DTMF tones.

Speaking of which, do you have a POTS line? Most modern phone service won't respond to DTMF directly any more. Or will this be used for something other than dialing on a phone line.

EDITED: 2026-02-23 to correct GP pins for PWM2.

Quote from: Chris Savage on Jan 22, 2026, 01:54 PMGentlemen,

Would this setup allow for writing assembly code and viewing results? I'm going to be placing some orders this weekend and wanted to get what would be needed to realize a Z80 development system. I need to check the other thread as well, since I thought there was hardware I needed to order for that as well.

Although I do not have RunCPM running on my RP2350-GEEK yet, I'm going to have to say "yes." The author/creator of RunCPM says, in his intro:

Quote from: MockbaTheBorg link=https://github.com/MockbaTheBorg/RunCPMRunCPM was written to serve as a test environment when I was restoring the only copy of Z80 MicroMumps v4.06 which exists online (https://github.com/MockbaTheBorg/MicroMumps).
Making changes, recompiling MicroMumps and loading it onto a regular CP/M emulator via a disk image every time I moved a bit forward on the restoration was becoming too time consuming. So I decided to write something that would allow me to run the executable right away after making any modifications.
RunCPM then evolved as more and more CP/M applications were added to its compatibility list.

My PicoCalc does have RunCPM, and there is a boat load of old CP/M stuff there, including several Z-80 languages and Z-80 assemblers: Microsoft Macro-80 assembler and Digital Research's ASM, RMAC & MAC assemblers. In fact, there is too much software for me - I need to weed out some of it (and organize what's left) so that I can make use of my RunCPM system.

The list of software included is listed on the Obsolescence Guaranteed site (https://obsolescence.wixsite.com/obsolescence/multicomp-fpga-cpm-demo-disk.) The list is truly impressive.

Quote from: Chris Savage on Dec 31, 2025, 09:05 AMI'm considering building something like this as a quick / cheap way to get people familiar with Z80 programming.

Z80 Emulator for Raspberry Pi Pico and other RP2040 based MCU boards (https://github.com/djbottrill/rp2040_z80_emulator)

It could run on this $4.00 Raspberry Pi Pico RP2040 (https://www.adafruit.com/product/4864?gad_source=1&gad_campaignid=21079227318&gbraid=0AAAAADx9JvRA4ZaQ1qTvuAsCId632A5MX&gclid=EAIaIQobChMIrMD42v7nkQMVuzIIBR3--ynEEAQYBSABEgInmvD_BwE) from Adafruit.

Do you have a favorite "textbook" for learning Z80 Assembly, preferably under CP/M? Also what assembler do you prefer?

I am thinking of going through a refresher "course" on Z80 Assembly programming. My PicoCalc, running RunCPM could be a great, portable CP/M system for doing the exercizes.

(https://files.granzeier.com/Downloads/SavageCircuits/Prayer%20Code.gif)

Quote from: granz on Jan 28, 2026, 12:55 PMDo you have a favorite "textbook" for learning Z80 Assembly, preferably under CP/M? Also what assembler do you prefer?

Nothing specific. I like books like Programming the Z80 from Rodnay Zaks, but typically when I'm programming, I just need a really good instruction reference. My favorite Z80 Handbook was lost many years ago.

As for assembly, I have always used TASM (Table-Driven Cross Assembler). I forget which version, but I know that everything I wrote to run under DOS wouldn't run on modern computers, however TASM runs in a CMD window on Windows 10 Pro (I haven't yet tried it on Windows 11). I even have a batch file that feeds it all the parameters, including the filename, and outputs the correct files.

Back in the day it would then copy the binary to my device programmer and launch a macro to program a 27C256.

Quote from: Chris Savage on Jan 28, 2026, 02:48 PM

Quote from: granz on Jan 28, 2026, 12:55 PMDo you have a favorite "textbook" for learning Z80 Assembly, preferably under CP/M? Also what assembler do you prefer?

Nothing specific. I like books like Programming the Z80 from Rodnay Zaks, but typically when I'm programming, I just need a really good instruction reference. My favorite Z80 Handbook was lost many years ago.

I was actually looking for a "how to get started with assembly programming under CP/M" book.

My favorite reference was the old Radio Shack Series 1 Editor/Assembler manual (https://www.classic-computers.org.nz/system-80/software-manuals/manuals-Editor-Assembler-Tandy.pdf (https://www.classic-computers.org.nz/system-80/software-manuals/manuals-Editor-Assembler-Tandy.pdf).) The reference section was fantastic - the layout was about perfect. Each machine op-code started on a new page - most were on a single page. Each op-code description had a complete description, including which registers were affected, and how.

Several other people, over the years, have mentioned that they thought that the EDTASM manual was great.

Quote from: Chris Savage on Jan 28, 2026, 02:48 PMAs for assembly, I have always used TASM (Table-Driven Cross Assembler). I forget which version, but I know that everything I wrote to run under DOS wouldn't run on modern computers, however TASM runs in a CMD window on Windows 10 Pro (I haven't yet tried it on Windows 11). I even have a batch file that feeds it all the parameters, including the filename, and outputs the correct files.

Back in the day it would then copy the binary to my device programmer and launch a macro to program a 27C256.

TASM is good, but like I said, I want to be able to use my PicoCalc as a portable CP/M system, and do all of my practicing/learning on the PicoCalc. If I ever get back to doing real Z80 work, I will probably use TASM, too. I believe that it can run under DOSBox-X, or at least a MS-DOS VirtuatBox session.

Quote from: granz on Jan 28, 2026, 05:26 PMTASM is good, but like I said, I want to be able to use my PicoCalc as a portable CP/M system, and do all of my practicing/learning on the PicoCalc. If I ever get back to doing real Z80 work, I will probably use TASM, too. I believe that it can run under DOSBox-X, or at least a MS-DOS VirtuatBox session.

I just confirmed that TASM does run in the Windows 11 Command Window. Seems slow for some reason, but does run. I will be sticking with it.

TASM_Scrn_V3.2.jpg

Quote from: Chris Savage on Jan 28, 2026, 07:56 PMI just confirmed that TASM does run in the Windows 11 Command Window. Seems slow for some reason, but does run. I will be sticking with it.

Thanks, that is good to know. However, especially after all the trouble that you have had with Win 11 (plus all the others that I have heard about their troubles,) I cannot imagine any situation where I will be installing Windows 11 any where. (One of the advantages of being retired - if someone offers me a job working with Windows, I can turn them down. 8) )

Quote from: granz on Jan 28, 2026, 09:45 PMThanks, that is good to know. However, especially after all the trouble that you have had with Win 11 (plus all the others that I have heard about their troubles,) I cannot imagine any situation where I will be installing Windows 11 any where. (One of the advantages of being retired - if someone offers me a job working with Windows, I can turn them down. 8) )

Well, it's been working since DOS. So that's a good thing. Justifies me sticking with it. The batch file I use to assemble is:

@ECHO OFF
TASM -80 -a -b -c -fff -h -l -s -y %1.SRC %1.OBJ %1.LST %1.SYM


Quote from: Chris Savage on Jan 28, 2026, 10:55 PMWell, it's been working since DOS. So that's a good thing. Justifies me sticking with it.

I'm not sure that I could call it working (at least not cleanly, nor well.) I remember doing installs of XP, and the first service pack that came out made the system so slow that it took over twenty minutes to boot, and to shut down. Being on client's time, I had to force shutdown, then I had to research why the slowdown, and how to fix it. If I recall, I had to format the drive then reinstall Win XP, and NOT do the update, until I did something else (I forget what that was.) There have been hundreds, if not thousands, of known bugs in various releases of Windows, and their upgrades (Service Packs.) Also, I recently heard that some of the Win 11 installs cause the system to brick - it wasn't clear if that just caused a reinstall, or actually bricked the system.

But, to get back to the subject...

Quote from: Chris Savage on Jan 28, 2026, 10:55 PMThe batch file I use to assemble is:

Code Select Expand

@ECHO OFF
TASM -80 -a -b -c -fff -h -l -s -y %1.SRC %1.OBJ %1.LST %1.SYM


Thanks, that should be useful if I get back to assembling under a DOS emulator under Linux.

Interesting: Just looked up the manual for TASM - when I first used this back in the '90s, I thought that TASM stood for Table Assembler, but just found out (again?) that the "T" stands for Telemark.

Another "interesting", in the beginning of the Introduction:

QuoteThe Telemark Assembler (TASM) is a table driven cross assembler for the MS-DOS and LINUX environments. Assembly source code, written in the appropriate dialect (generally very close to the manufacturers assembly language), can be assembled with TASM, and the resulting object code transferred to the target microprocessor system via PROM or other mechanisms.

I had not realized that TASM works in Linux! TASM just went way up in my estimation.

Quote from: granz on Jan 29, 2026, 07:54 AMI had not realized that TASM works in Linux! TASM just went way up in my estimation.

LOL TASM just works. I have used it to assemble on at least 4 different platforms, including the Z80, 6502, 6809 and 8085, as well as variants of these.

Gentlemen,

If I may ask (I have so many things going on at once), what was the consensus with regards to building a Z80 emulator? In the first post I mentioned a cheap hardware platform and some software. But our conversation evolved across two threads and I wanted to order some hardware this weekend for it.

What sounds like the best bang for the buck for build an emulator for those who want to assemble for Z80, without an actual Z80 IC?

I still think that the Pico with RunCPM will be the best deal:

Amazon:

• SD Card Breakout (2 ea) - $5.49 - https://www.amazon.com/DIYables-Adapter-Arduino-ESP8266-Raspberry/dp/B0BXKLNN2L
• Raspberry Pi Pico H w/ USB Cable - $9.90 - https://www.amazon.com/Microcontroller-Development-Pre-Soldered-Dual-Core-Multi-Function/dp/B0DSBQS5ZF/
• 830 Point Breadboard - $4.59 - https://www.amazon.com/California-JOS-Breadboard-Solderless-Distribution/dp/B0BRQX6G3T/
• 1 GB Micro SD Card - $7.79 - https://www.amazon.com/Lerdisk-Wholesale-1GB-Produced-Authorized/dp/B0D3KWY34B
• Hookup Wire - $3.86 - https://www.amazon.com/MECCANIXITY-Breadboard-Electronics-Electronic-Projects/dp/B0F1YDQ53Q

Total - $31.63 + sales tax
No shipping fee for Prime Members.
Price could be considerably less for someone who can solder.
No soldering, nothing else to purchase.
RunCPM firmware is a single file that is extremely easy to install on the Pico - great for complete beginner.

The first two links are identical.  :P

Thank you for catching that, the link has been corrected. I also put in my description of that item that it includes the USB cable. That particular sale item also includes the three-pin male header for the Debug port, but for a total beginner they could simply ignore that.

If you like this, next payday (18 Feb) I will order this set, and do a write-up on how to put this kit together and set it up for RunCPM. It would be better if I put together an A: drive image specifically for this kit - the drive images that are recommended by the RunCPM project are WAY too much for a beginner. The image that I will set up will just have the assembler/linker, an editor (probably ZDE,) a simple language like BASIC, maybe a word processor (WordStar?) and maybe a game, or so.

The only thing that would be required beyond this set would be a computer/tablet/phone. I will give directions for setting up a Linux, a Windows, a Mac (I just need to set up one of my Mac Minis) computer and an Android tablet/phone. I would need someone else to add the instructions for an IOS I-Pad/I-Phone, as I don't have any of those.

How does this sound to you?

Quote from: granz on Feb 07, 2026, 06:19 AMThe image that I will set up will just have the assembler/linker, an editor (probably ZDE,) a simple language like BASIC, maybe a word processor (WordStar?) and maybe a game, or so.

The only thing that would be required beyond this set would be a computer/tablet/phone. I will give directions for setting up a Linux, a Windows, a Mac (I just need to set up one of my Mac Minis) computer and an Android tablet/phone. I would need someone else to add the instructions for an IOS I-Pad/I-Phone, as I don't have any of those.

How does this sound to you?

Well, I do have a couple of questions. Why did you choose a 1GB SD card? I have noticed that on typical R-Pi boards, the included / recommended SD card size has steadily increased over time, though I have never taken note of the used space after an OS has been installed. Often, larger cards are cheaper. So unless a small card is necessary, it is often cheaper to go larger. I wasn't sure if there was a size limitation on the driver you're going to be using?

Also,

Right now I have all the parts you linked in my Amazon cart. With two of everything (except what I already have). My intention is to follow what you're doing on my end. I am going to send the items in the list to you after they arrive. I was the one asking about doing this and I do not have the time to experiment with this, therefore, I will provide the parts if you'll write up a tutorial on putting this together. Depending on the results, I may put it up on the main website as a project. But first I want to see how it works out with the specified parts.

I will delay placing the order until I hear back from you on the SD card size specifications.

Quote from: Chris Savage on Feb 08, 2026, 10:41 PMWell, I do have a couple of questions. Why did you choose a 1GB SD card? I have noticed that on typical R-Pi boards, the included / recommended SD card size has steadily increased over time, though I have never taken note of the used space after an OS has been installed. Often, larger cards are cheaper. So unless a small card is necessary, it is often cheaper to go larger. I wasn't sure if there was a size limitation on the driver you're going to be using?

I have had a pretty rough several days, and was exhausted. When you texted, I had already gone to bed. Starting to feel a bit better, and no appointments until Friday, so another few days of early-to-bed, late-to-rise  ;D will, hopefully, get me better rested.

As I mentioned in the texting chat, I spec'ed the lowest price for everything. I also wanted a single source for everything - no multiple orders. Also, with Amazon, many people have the Prime membership, and shipping on all of that stuff is free for Prime. Plus, a whopping 1 GB of disk space is monstrously huge for a CP/M system. CP/M was meant for floppies, and when hard drives came out, only supported 5MB (max of 8 MB per drive.) Regular Pi systems need far more space than CP/M, however they are able to do way more - but you wanted a system for Z-80 assembly programming, and this hardware, along with some (free) CP/M software will do the job.

Now, that doesn't mean that this is the bottom-of-the-barrel pricing. Anyone who has fair-to-decent soldering skills can get cheaper by soldering the kit themselves, and lower prices can be found on places like AliExpress (if you are willing to risk it,) or stopping by their local MicroCenter, or other electronics store. And, most people who are interested in this project would probably have a breadboard, and jumper wires, etc. but, like I said the idea for these choices was to be easily available to the lowest common denominator in newbies, for the cheapest price.

Quote from: Chris Savage on Feb 08, 2026, 10:41 PMAlso,

Right now I have all the parts you linked in my Amazon cart. With two of everything (except what I already have). My intention is to follow what you're doing on my end. I am going to send the items in the list to you after they arrive. I was the one asking about doing this and I do not have the time to experiment with this, therefore, I will provide the parts if you'll write up a tutorial on putting this together. Depending on the results, I may put it up on the main website as a project. But first I want to see how it works out with the specified parts.

I will delay placing the order until I hear back from you on the SD card size specifications.

Well, I appreciate that; I can do that. Also, if you have Prime, it would be cheaper for you to make two orders, one shipped to you, and the other sipped to me. It would save you the cost of shipping from your place to mine. Plus, save the price of the box, and packing.

By the way, if you do not have a Prime subscription, let me purchase these parts, and have one set shipped to you. I do have a Prime membership.

Quote from: granz on Feb 09, 2026, 08:18 AMI have had a pretty rough several days, and was exhausted. When you texted, I had already gone to bed. Starting to feel a bit better, and no appointments until Friday, so another few days of early-to-bed, late-to-rise  ;D will, hopefully, get me better rested.

I can appreciate that. I am home from work today. Clearing snow two days in a row took a toll on me. My back and feet just can't do it. Recovering today, since it's not snowing.

Quote from: granz on Feb 09, 2026, 08:18 AMAs I mentioned in the texting chat, I spec'ed the lowest price for everything. I also wanted a single source for everything - no multiple orders. Also, with Amazon, many people have the Prime membership, and shipping on all of that stuff is free for Prime. Plus, a whopping 1 GB of disk space is monstrously huge for a CP/M system. CP/M was meant for floppies, and when hard drives came out, only supported 5MB (max of 8 MB per drive.) Regular Pi systems need far more space than CP/M, however they are able to do way more - but you wanted a system for Z-80 assembly programming, and this hardware, along with some (free) CP/M software will do the job.

I guess I was thinking about the overhead of the R-Pi OS, but that's fine. You're right. My sole interest in this is a cheap Z80 assembly platform.

Quote from: granz on Feb 09, 2026, 08:18 AMWell, I appreciate that; I can do that. Also, if you have Prime, it would be cheaper for you to make two orders, one shipped to you, and the other sipped to me. It would save you the cost of shipping from your place to mine. Plus, save the price of the box, and packing.

Obviously, you're thinking better than I am. I didn't even think about that. I will place two orders right now and have one shipped to you.

Quote from: Chris Savage on Feb 09, 2026, 10:54 AMI guess I was thinking about the overhead of the R-Pi OS, but that's fine. You're right. My sole interest in this is a cheap Z80 assembly platform.

With the RunCPM firmware, that is the OS, not Raspberry Pi OS. RunCPM has a pretty small footprint (325 KB)! :o And, that is completely onboard the Pico - the entire SD card is for CP/M files.

Quote from: Chris Savage on Feb 09, 2026, 10:54 AMObviously, you're thinking better than I am. I didn't even think about that. I will place two orders right now and have one shipped to you.

Thanks, I'll get started on the write-up.

Quote from: granz on Feb 09, 2026, 11:31 AMWith the RunCPM firmware, that is the OS, not Raspberry Pi OS. RunCPM has a pretty small footprint (325 KB)! :o And, that is completely onboard the Pico - the entire SD card is for CP/M files.

I ordered everything in the list for you. For me, I ordered the R-Pi, SD Card and SD Card Sockets. I have plenty of breadboards and wires.

As with the project that @Jeff_T is working on, once I complete things on my end, I may post the project in my own words to the main website, with attribution to you both as well as linking to your posts here in the Member Project section.

As is the case pretty much every time with Amazon, my order, which was due today, is now late and expected tomorrow instead.  ::)

Quote from: Chris Savage on Feb 11, 2026, 03:24 PMAs is the case pretty much every time with Amazon, my order, which was due today, is now late and expected tomorrow instead.  ::)

Unfortunately that is becoming the norm for Amazon. The other day, I was trying to set up one of my new Raspberry Pi systems as Spock, and realized that I needed a micro-HDMI to HDMI adapter. I selected the option to "get it by tomorrow" morning in the search parameters, and a set came up that looked good. However, when I actually tried to order the things, they were two-day (not the over night that I searched for.  >:( ) I paid the additional money for overnight - by 11:00 in the morning. Of course, even with spending the extra shipping cost, it did not come until late yesterday. I cancelled the order, and got my money back - I did not like paying the extra, especially when it did not arrive by the time that they said it would!

I ended up using an older Pi 3 (has a full-sized HDMI port) for Spock, and we were able to watch a movie last night on Spock. So, I may just use that Pi 3 for Spock, and use the Pi 5 (with the micro-HDMI) for something else. So, I just placed a regular "Prime" order for some adapters, and will accept 2- to 3-day delivery, without the extra charge.

Amazon is getting worse, and worse. I wish that we had a MicroCenter (or better yet, a Fry's or something) close by.

Well, I got everything except for the SD Card Breakouts - they should arrive on Monday.
(https://files.granzeier.com/Downloads/SavageCircuits/RunCPM%20Parts.jpg)

I did get a bit of a start there, I received the SD Card, but it was a micro card - I thought that the breakout was full-sized. It only took a minute, or two, to find out that they were both for micro- and not full-sized.

The breadboard does come with some jumper wires, but they are all male-to-female jumper wires. I'm not sure how the female connectors would help with a breadboard, but they were there any way. Yet another annoyance for the beginner - we may want to choose another breadboard, one without the jumper wires that the buyer needs to just "throw out" (get rid of them.) That would just make the newbie wonder why he should waste his money.

Interestingly, there is no mention of jumper wires in the description on that Amazon page. I guess that they just added the wires as a bonus - makes it more difficult to choose these for a beginners kit, although great for non-beginners.

If you were to decide to sell these kits all in one pack, then you could save a huge amount of money by buying in bulk, and soldering things yourself. This is just for the newbie who is wanting to get into this assembly programming by him-(her-?)self.

Quote from: granz on Feb 12, 2026, 02:35 PMI did get a bit of a start there, I received the SD Card, but it was a micro card - I thought that the breakout was full-sized. It only took a minute, or two, to find out that they were both for micro- and not full-sized.

Yeah, almost nobody uses full-sized SD cards anymore. Just a fact of life, I guess.

Quote from: granz on Feb 12, 2026, 02:35 PMThe breadboard does come with some jumper wires, but they are all male-to-female jumper wires. I'm not sure how the female connectors would help with a breadboard, but they were there any way.

Here is where my own recent experience shines. The vast majority of sensors and accessories I get for the Arduino have pins on them. I use the M-F wires to connect these devices to the breadboard. You can see an example here: New Project (https://savagechats.com/index.php?topic=319.msg1240#msg1240)

It's especially nice when the pins are such that you can't actually plug the board into the breadboard.

Quote from: granz on Feb 12, 2026, 02:35 PMIf you were to decide to sell these kits all in one pack, then you could save a huge amount of money by buying in bulk, and soldering things yourself. This is just for the newbie who is wanting to get into this assembly programming by him-(her-?)self.

Yeah, something to think about, especially since you've identified other uses for it than what my interests are.

P.S. - My last part came in, so now I have everything I need to realize your configuration.

P.P.S. - Two things about these card readers that I am mildly disappointed with is the PCB edges (rough) and the lack of a card detect pin. I know we're trying to keep costs down, but that's something I use in my own designs, usually.

Quote from: Chris Savage on Feb 12, 2026, 06:35 PM

Quote from: granz on Feb 12, 2026, 02:35 PMI did get a bit of a start there, I received the SD Card, but it was a micro card - I thought that the breakout was full-sized. It only took a minute, or two, to find out that they were both for micro- and not full-sized.

Yeah, almost nobody uses full-sized SD cards anymore. Just a fact of life, I guess.

Yes, but as you emphasized, almost... The PicoCalc actually uses a full-sized SD card. Personally, with my not-so-great fine motor control, I would prefer the full-sized cards anyway. :-[

Quote from: Chris Savage on Feb 12, 2026, 06:35 PM

Quote from: granz on Feb 12, 2026, 02:35 PMThe breadboard does come with some jumper wires, but they are all male-to-female jumper wires. I'm not sure how the female connectors would help with a breadboard, but they were there any way.

Here is where my own recent experience shines. The vast majority of sensors and accessories I get for the Arduino have pins on them. I use the M-F wires to connect these devices to the breadboard. You can see an example here: New Project (https://savagechats.com/index.php?topic=319.msg1240#msg1240)

There is that, however most of those sensors' breakouts use 0.1" pin spacing, and they do fit into the breadboard. It actually makes the attachment of those sensors more stable, and secure. Yes, there are some that use non-standard pin spacing, but as far as I have seen, that is a minority. Either way, it is nice (for a more-advanced hobbyist) for them to include them - I just would have preferred the male-to-male wires for this.

Quote from: Chris Savage on Feb 12, 2026, 06:35 PMIt's especially nice when the pins are such that you can't actually plug the board into the breadboard.

Quote from: granz on Feb 12, 2026, 02:35 PMIf you were to decide to sell these kits all in one pack, then you could save a huge amount of money by buying in bulk, and soldering things yourself. This is just for the newbie who is wanting to get into this assembly programming by him-(her-?)self.

Yeah, something to think about, especially since you've identified other uses for it than what my interests are.

P.S. - My last part came in, so now I have everything I need to realize your configuration. (Emphasis mine - AG3)

Did you (accidentally) order a second micro-SD card, and breadboard, for me? Last night, I noticed three packages on my porch; two of them were the card and breadboard (the third was some stuff that I did order.) Since you did receive your components, it may have been that you accidentally ordered these for me, or it was an Amazon mistake. You may want to check your bank to make sure that you were not charged for these extras.

Quote from: Chris Savage on Feb 12, 2026, 06:35 PMP.P.S. - Two things about these card readers that I am mildly disappointed with is the PCB edges (rough) and the lack of a card detect pin. I know we're trying to keep costs down, but that's something I use in my own designs, usually.

Quote from: granz on Feb 13, 2026, 07:14 AMYes, but as you emphasized, almost... The PicoCalc actually uses a full-sized SD card. Personally, with my not-so-great fine motor control, I would prefer the full-sized cards anyway. :-[

I get it...on circuit boards the larger sockets are easier to solder as well. The microSD card sockets are challenging for some to solder, and some boards, like the ones Parallax used to sell, had pads for them. The socket was optional.

Quote from: granz on Feb 13, 2026, 07:14 AMThere is that, however most of those sensors' breakouts use 0.1" pin spacing, and they do fit into the breadboard. It actually makes the attachment of those sensors more stable, and secure. Yes, there are some that use non-standard pin spacing, but as far as I have seen, that is a minority. Either way, it is nice (for a more-advanced hobbyist) for them to include them - I just would have preferred the male-to-male wires for this.

So, the link I posted actually showed what I meant to say, but failed to convey. Some of the boards I get have two rows of pins, instead of one, despite having 0.1" spacing. This is similar to the AppMod connectors on older Parallax boards. Even when I do have a SIP header, there often isn't room on the breadboard for the large LCD I recently connected to a breadboard, so I had to use the M-F wires. I just post this for those who wouldn't think about this as a reason to have these on hand. I bought M-M, M-F and F-F in multiple lengths, just so I'm covered. The wires can be gotten cheap on Amazon in multi-packs. Something to consider for those who use a lot of accessories.

Quote from: granz on Feb 13, 2026, 07:14 AMDid you (accidentally) order a second micro-SD card, and breadboard, for me? Last night, I noticed three packages on my porch; two of them were the card and breadboard (the third was some stuff that I did order.) Since you did receive your components, it may have been that you accidentally ordered these for me, or it was an Amazon mistake. You may want to check your bank to make sure that you were not charged for these extras.

I think your order contained five (5) items (though the SD card boards are a pack of two) and I got three (3) items. What else did you get? Whatever it is, it's a FREE bonus, because I believe the orders look accurate on my app, though in checking, I just noticed that it still says the wires and Pico are arriving today and the SD card boards are arriving Monday. It will be interesting to see if you get those deliveries. If you do, let me know.

Quote from: Chris Savage on Feb 13, 2026, 08:06 AM

Quote from: granz on Feb 13, 2026, 07:14 AMThere is that, however most of those sensors' breakouts use 0.1" pin spacing, and they do fit into the breadboard. It actually makes the attachment of those sensors more stable, and secure. Yes, there are some that use non-standard pin spacing, but as far as I have seen, that is a minority. Either way, it is nice (for a more-advanced hobbyist) for them to include them - I just would have preferred the male-to-male wires for this.

So, the link I posted actually showed what I meant to say, but failed to convey. Some of the boards I get have two rows of pins, instead of one, despite having 0.1" spacing. This is similar to the AppMod connectors on older Parallax boards. Even when I do have a SIP header, there often isn't room on the breadboard for the large LCD I recently connected to a breadboard, so I had to use the M-F wires. I just post this for those who wouldn't think about this as a reason to have these on hand. I bought M-M, M-F and F-F in multiple lengths, just so I'm covered. The wires can be gotten cheap on Amazon in multi-packs. Something to consider for those who use a lot of accessories.

I have to admit that I did not go to that link, but things like the ESP-01 (breadboard unfriendly) came to my mind right away. Yep, things like that, or the male headers on the Raspberry Pi GPIOs, make the female jumper wires much more handy. And, like you, I also have a pretty large assortment of all three of those kinds of jumper wires.

But, again (just for this use case) the male-to-male jumpers would have been useful, where as the male-to-female jumpers could cause confusion, and price concerns, for the buyer. We will need to consider maybe using a different source for this, and the SD breakout board that you mentioned.

Quote from: Chris Savage on Feb 13, 2026, 08:06 AM

Quote from: granz on Feb 13, 2026, 07:14 AMDid you (accidentally) order a second micro-SD card, and breadboard, for me? Last night, I noticed three packages on my porch; two of them were the card and breadboard (the third was some stuff that I did order.) Since you did receive your components, it may have been that you accidentally ordered these for me, or it was an Amazon mistake. You may want to check your bank to make sure that you were not charged for these extras.

I think your order contained five (5) items (though the SD card boards are a pack of two) and I got three (3) items. What else did you get? Whatever it is, it's a FREE bonus, because I believe the orders look accurate on my app, though in checking, I just noticed that it still says the wires and Pico are arriving today and the SD card boards are arriving Monday. It will be interesting to see if you get those deliveries. If you do, let me know.

I did get all four of my items (still waiting for the SD breakouts; due Monday.) The items that I got yesterday were in addition to the items that I received the other day.

Just so long as you did not get charged for the extras.

Quote from: granz on Feb 13, 2026, 09:17 AMBut, again (just for this use case) the male-to-male jumpers would have been useful, where as the male-to-female jumpers could cause confusion, and price concerns, for the buyer. We will need to consider maybe using a different source for this, and the SD breakout board that you mentioned.

Once you've posted your project here, I will follow your guide to build the project. While doing so, I will create a project on Savage///Circuits which accredits your work and links to it. Depending on what I find, I may start off by building five (5) kits with everything needed and post them on the MeBay page. We can always add more if they become popular.

Quote from: granz on Feb 13, 2026, 09:17 AMI did get all four of my items (still waiting for the SD breakouts; due Monday.) The items that I got yesterday were in addition to the items that I received the other day. Just so long as you did not get charged for the extras.

I'm good. Not gonna lie though...I am curious what you got extra.  ;)

Correction: This "extra" breadboard came with male-to-male jumper wires. While these are better for our specific case, it is a bit disturbing in that they have not standardized on what they add to the breadboard. This is OK (actually very nice) for hobbyists, but could cause a lot of troubles for a newbie. What jumper wires did you get in your breadboard pack?

I think that, if we give a BOM list, like above, we need to select a breadboard that either comes with M-M jumper wires (then we can drop the additional jumper wires) or no jumper wires at all. This is weird - the first time it has been concerning to me that I get more than what was purchased.  ???

Of course, this is completely irrelevant to the packs that you put together - you can just make sure that each pack has only what is needed.

Quote from: granz on Feb 13, 2026, 02:31 PMCorrection: This "extra" breadboard came with male-to-male jumper wires. While these are better for our specific case, it is a bit disturbing in that they have not standardized on what they add to the breadboard. This is OK (actually very nice) for hobbyists, but could cause a lot of troubles for a newbie.

Are you saying the "extra" package you got was another breadboard with M-M wires?

Quote from: granz on Feb 13, 2026, 02:31 PMWhat jumper wires did you get in your breadboard pack?

I didn't order a breadboard or wires, since I have so many on my bench already.

Quote from: granz on Feb 13, 2026, 02:31 PMI think that, if we give a BOM list, like above, we need to select a breadboard that either comes with M-M jumper wires (then we can drop the additional jumper wires) or no jumper wires at all.

Sounds good. We'll refine things as the projects becomes finalized for the kit on the main website. Until then, I'm just following your lead based on what you're using.

The following was supposed to be posted this morning, shortly after Chris' reply # 48:

Quote from: GranzLike I said, in reply #45, I got an extra SD card (have not opened it yet, but it is in the same type envelope as the first one that I got,) and an extra breadboard set (with the same male-to-female jumper wires.) Kind of strange that I got those two, and nothing more (so far.)

I use two different laptops every day. Apparently this got typed in, but then I got distracted and never actually posted it.

And, the plot thickens; I just received another Pico. This is exactly the same make and seller as the first one that I received. Something strange here: the Pico that I received last week came through Amazon delivery, but this one (same seller) came through the U.S. Postal Service, and was in our mailbox. ??? First of all, why did they send me a duplicate of (most of) your order, and secondly, why did one come through Amazon delivery, and the other through the mail? Weirdness abounds.  :P

All I can say is, "BONUS!!!" Lucky you! LOL  ;)

Quote from: granz on Feb 12, 2026, 02:35 PMWell, I got everything except for the SD Card Breakouts - they should arrive on Monday.
(https://files.granzeier.com/Downloads/SavageCircuits/RunCPM%20Parts.jpg)

Well, that "should arrive on Monday" has come, and gone. ::) So, now that the SD Card breakouts are a week late, could you check the status on your Amazon account to see if they were marked as delivered? If they show as delivered, you will need to file a claim that they were not delivered.

Well, as of right now, here's what my Amazon app says...I will DM you the UPS tracking number now. Optionally, I could cancel and ship you directly one of the TWO I got. But I bet you'd like the spare? Your choice.

Amazon_Shipping_Delay_granz.jpg

Hah! UPS says that they have not even received the package yet.

I'll go ahead and wait; thanks.

I'm re-thinking our target market right now - continuing on with getting started with CP/M assembly programing intro.

Quote from: granz on Feb 23, 2026, 01:33 PMI'm re-thinking our target market right now - continuing on with getting started with CP/M assembly programing intro.

That's fine, just as long as the tools for assembling for Z80 are a part of the end package, that's what I am interested in. Everything else is bonus material, which is great for average end users, but not part of my initial interest in the project. So yeah, have fun with whatever resources you want to add in for software or focus, as long as we retain Z80 ASM dev tools / information.  8)

P.S. - I really wish the stock install of SMF had better smileys, but I promised myself I wouldn't mod this software in any way to minimize issues I experienced in the past. Bad enough I've experienced some related to the anti-spam plug-in.

Quote from: granz on Feb 23, 2026, 01:33 PMHah! UPS says that they have not even received the package yet.

I got a notification this morning that it's out for delivery.

Okay, I'll keep a watch for it.

Okay, I've received it, but the box was opened and one of the packs was torn down the side and the SD Card breakout was sitting outside the wrapper. This did not happen in shipping - they just took a return, and without even checking it out they just sold it again as new. They should probably get a minimum review (they earned a zero) and let them know that you don't appreciate paying for new, and getting returned merchandise.

Quote from: granz on Feb 25, 2026, 05:09 PMOkay, I've received it, but the box was opened and one of the packs was torn down the side and the SD Card breakout was sitting outside the wrapper. This did not happen in shipping - they just took a return, and without even checking it out they just sold it again as new. They should probably get a minimum review (they earned a zero) and let them know that you don't appreciate paying for new, and getting returned merchandise.

I've had this issue so many times. As someone who pays for Prime membership, I am constantly dismayed at how much less I get for my money every month. More often than not, I do not get the 2-day shipping promised when I placed the order. Most orders are followed by, "Your package has been delayed". Likewise, I no longer review any item on Amazon, because they reject any review that isn't specific to your experience with the product as intended for use. When I have mentioned the way a product is packaged or arrived (damaged), those reviews are rejected.

Some points that I/we need to consider

• Quote from: granz on Feb 23, 2026, 01:33 PMI'm re-thinking our target market right now - continuing on with getting started with CP/M assembly intro.
  

  Our target market would, most likely, be hackers/hobbyists and not true newbies. It seems to me that someone with no experience in electronics/controllers/etc would probably start with more modern stuff like Arduino, Pico, Raspberry Pi, PIC, etc. So, this will probably be more geared to the hobbyist who is interested in learning retro-programming.
  
  
• The assembler: CP/M was originally written for the Intel 8080 CPU. As such, the Digital Research ASM assembler uses Intel mnemonics, rather than Zilog mnemonics. On many of the instructions, the source and destination are swapped from the Intel version. You had mentioned that you wanted this to be for the Z-80 CPU. The Z-80 does run all Intel 8080 object code, but the source code (what the programmer writes) would be different with Z-80 vs. I8080 object. What would you prefer, stick to Z-80 (my recommendation,) or Intel assembly?
  
  If we stick to Z-80 code, a good recommendation (from Bill McMullen on Google Retro Comp group) is:
  

  Quote from: Bill McMullen - https://groups.google.com/g/retro-comp/c/_aLLm6uOjgw?pli=1My preference for Z80 assembler code is to use Microsoft's M80 / L80.  The reason is simply that it is quite commonly available, has a rudimentary macro facility and also the .PHASE / .DEPHASE instructions which are really handy for moving code around such as from ROM to RAM.

  I fully agree, for all the reasons that he lists
  He even gives his SUBmit script (the CP/M equivalent of a DOS batch file) to launch the Microsoft assembler, and linker.
  
  
• Thoroughness - how newbie-ish do you want this? I try to make most of my directions very thorough. Do you want directions like the "Learn About Microcontrollers" Instructable (https://www.instructables.com/Learn-About-Microcontrollers/), or higher level (considering the target market mentioned above)?
  
  
• Scope - Am I just supposed to do the instructions for the hardware and setting up the software? Are you going to write the introduction to Z-80 programming under CP/M?
  
  

Can you think of anything else that we should consider?

I'm not going to quote, since your reply covers a lot. What I will say is this...you're right that Z80 assembly would be for the retro-computer enthusiast. I suppose, so would CP/M. If you look back at the first post in this thread (https://savagechats.com/index.php?msg=3834), this whole thing cam about because, while looking for Z80 emulation, I found the Z80 Emulator for Raspberry Pi Pico and other RP2040 based MCU boards (https://github.com/djbottrill/rp2040_z80_emulator) and thought that would be an inexpensive way to do either / both.

The problem was, I wasn't sure if there was a Z80 assembler for CP/M. I have used TASM for DOS / Linux since day one. The ONLY CP/M system I have is the RC2014 Pro Homebrew Z80 Computer Kit (https://savagecircuits.com/rc2014-pro-homebrew-z80-computer-kit/) on the main site, which does have an option to boot to CP/M from a Compact Flash card, which I have done.

However, I didn't buy it for the CP/M, I bought it for the Z80, I/O and ease of expansion. It uses a serial interface via terminal, so I assumed the link above would be the same. But my interest was in writing assembly code for it, which I have been doing as I work on it. I thought we were making an SD Card image that would boot the RP2040 into CP/M and provide an assembler for Z80 assembly, plus whatever you had in mind. Is that still possible?

Quote from: Chris Savage on Mar 23, 2026, 05:20 PMI'm not going to quote, since your reply covers a lot. What I will say is this...you're right that Z80 assembly would be for the retro-computer enthusiast. I suppose, so would CP/M.

Okay, so hobbyist-level it is. Thanks.

Quote from: Chris Savage on Mar 23, 2026, 05:20 PMIf you look back at the first post in this thread (https://savagechats.com/index.php?msg=3834), this whole thing cam about because, while looking for Z80 emulation, I found the Z80 Emulator for Raspberry Pi Pico and other RP2040 based MCU boards (https://github.com/djbottrill/rp2040_z80_emulator) and thought that would be an inexpensive way to do either / both.

The problem was, I wasn't sure if there was a Z80 assembler for CP/M.

There are several. We will go with the Microsoft M80 and T80 combo. Nice and easy.

Quote from: Chris Savage on Mar 23, 2026, 05:20 PMI have used TASM for DOS / Linux since day one. The ONLY CP/M system I have is the RC2014 Pro Homebrew Z80 Computer Kit (https://savagecircuits.com/rc2014-pro-homebrew-z80-computer-kit/) on the main site, which does have an option to boot to CP/M from a Compact Flash card, which I have done.

We will do all of our programming work on the Pico itself (using a serial terminal emulator, of course.)

The advantage of using a serial terminal emulator is that you can develop in TASM and upload it to the Pico using CP/M's XMODEM program (or any of several other commands.) But, we will concentrate on developing under CP/M itself - unless you would prefer development on the PC, using TASM. Let me know - they are both doable.

Quote from: Chris Savage on Mar 23, 2026, 05:20 PMHowever, I didn't buy it for the CP/M, I bought it for the Z80, I/O and ease of expansion.

I do not believe that the RunCPM system allows access to any of the GPIO capabilities of the Raspberry Pi Pico. RunCPM will give the environment of a 1970's business-class system. It will be more for writing standard user type programs, rather than control-system programs. Will this scuttle this project?

Quote from: Chris Savage on Mar 23, 2026, 05:20 PMIt uses a serial interface via terminal, so I assumed the link above would be the same. But my interest was in writing assembly code for it, which I have been doing as I work on it. I thought we were making an SD Card image that would boot the RP2040 into CP/M and provide an assembler for Z80 assembly, plus whatever you had in mind. Is that still possible?

Kind of... We will be using a firmware file installed onto the Pico, plus a set of Z-80 programs on the SD card. I will be setting up a downloadable .ZIP file to extract onto the SD card. This will give the Pico CP/M system a single hard drive (A:) with the CP/M Operating System and necessary utilities in user area 0 (like the root of the hard drive.) The programming software (editor, assembler, linker, etc.) will be in user area 1 (like a sub-directory.) That will be all that I will provide (to keep it simple,) however it is very easy to get up to 16 hard drives with up to 16 user areas each - just create additional sub-directories on the SD card.

Interestingly, I just saw this on Hack-A-Day:
(https://hackaday.com/wp-content/uploads/2026/03/picoZ80_vs_realZ80.png?w=800)

https://hackaday.com/2026/03/23/picoz80-is-a-drop-in-replacement-for-everyones-favorite-zilog-cpu/

Funny timing, considering our project here.

Quote from: granz on Mar 23, 2026, 05:53 PMThe advantage of using a serial terminal emulator is that you can develop in TASM and upload it to the Pico using CP/M's XMODEM program (or any of several other commands.) But, we will concentrate on developing under CP/M itself - unless you would prefer development on the PC, using TASM. Let me know - they are both doable.

I like the flexibility of having both options available.

Quote from: granz on Mar 23, 2026, 05:53 PMI do not believe that the RunCPM system allows access to any of the GPIO capabilities of the Raspberry Pi Pico. RunCPM will give the environment of a 1970's business-class system. It will be more for writing standard user type programs, rather than control-system programs. Will this scuttle this project?

Not at all. This is for learning and experience. If you really want a control board, use a real Z80.  ;)

Quote from: granz on Mar 23, 2026, 08:25 PMInterestingly, I just saw this on Hack-A-Day. Funny timing, considering our project here.

So the question is, are these for sale? If so, how much? I followed through several links, but could not find them for sale at a glance.

Quote from: Chris Savage on Mar 23, 2026, 09:30 PM

Quote from: granz on Mar 23, 2026, 05:53 PMThe advantage of using a serial terminal emulator is that you can develop in TASM and upload it to the Pico using CP/M's XMODEM program (or any of several other commands.) But, we will concentrate on developing under CP/M itself - unless you would prefer development on the PC, using TASM. Let me know - they are both doable.

I like the flexibility of having both options available.

Both are available, but I will not be covering the on-PC option in this setup.

Quote from: Chris Savage on Mar 23, 2026, 09:30 PM

Quote from: granz on Mar 23, 2026, 05:53 PMI do not believe that the RunCPM system allows access to any of the GPIO capabilities of the Raspberry Pi Pico. RunCPM will give the environment of a 1970's business-class system. It will be more for writing standard user type programs, rather than control-system programs. Will this scuttle this project?

Not at all. This is for learning and experience. If you really want a control board, use a real Z80.  ;)

I fully agree - we'll do this for education.

Quote from: Chris Savage on Mar 23, 2026, 09:30 PM

Quote from: granz on Mar 23, 2026, 08:25 PMInterestingly, I just saw this on Hack-A-Day. Funny timing, considering our project here.

So the question is, are these for sale? If so, how much? I followed through several links, but could not find them for sale at a glance.

On @eaw's site (https://eaw.app/picoz80/), about one third of the way down, there is a section titled Build Instructions. It looks like you need to build your own boards for now.

Sounds good. As you post information, I will build on my end and draft to the main site with photos of my build.

I decided to join the fun ;D . My setup is the following:
Pico WH
GeeekPi Basic Starter Kit (https://www.amazon.com/GeeekPi-Raspberry-BreadBoard-Half-Size-Breadboard/dp/B093GXJ64J/ref=sr_1_1?crid=3U8RPBC1KE0C&dib=eyJ2IjoiMSJ9.t0LsngnMutmbmUCvvMB-DIk0u-6yisq891QUipOql8vpTXfNoVcb7d38_1sVUvuADlMMbz65PdQVo6k8_x-UkkfqzFhl8TJQ8qyPae94gx0pmfby3AVoK8oKUdb2JAI3EJpOX7NIxhJyYBwxh1JoxQAS2nU1cs98bV2d9tZOogsa4TS75nIUUFeRrAYtvj3MYuwx4ZB3ol-rRGEyU65Fv-3uofQwaoAOQhI9gkBQARw.5nVsPbvJ7UOG-7_-9svp2FwrIkxKxgFf7jtRflL6Y-g&dib_tag=se&keywords=pico+breadboard+kit&qid=1774489042&sprefix=pico+bread%2Caps%2C196&sr=8-1) for the breadboard
Parallax 32312 Micro SD Card adapter

The GeeekPi costs $13.59, a little more than the breadboard @granz suggested, It comes with a smaller breadboard but it has a socket for the Pico and well labeled pins to connect jumpers to. It would be a good starter for someone new to microcontrollers. It does have a design flaw though. The input for the onboard buzzer is left floating so when you power the Pico it usually starts buzzing unless you jumper the buzzer input to ground,

I did have a SD card init problem due to using the Pico's 3.3V output for the SD card. I did the suggested doubling of the ground and power jumpers and I got the SD card running so now I'm running RunCPM.

Next I'll try the emulator that Chris pointed out to see if I can use the Pico's Wifi.

Quote from: MicroNut on Mar 25, 2026, 10:03 PMNext I'll try the emulator that Chris pointed out to see if I can use the Pico's Wifi.

Very interesting. Can't wait to see what you come up with.

Quote from: MicroNut on Mar 25, 2026, 10:03 PMI decided to join the fun ;D . My setup is the following:
Pico WH
GeeekPi Basic Starter Kit (https://www.amazon.com/GeeekPi-Raspberry-BreadBoard-Half-Size-Breadboard/dp/B093GXJ64J/ref=sr_1_1?crid=3U8RPBC1KE0C&dib=eyJ2IjoiMSJ9.t0LsngnMutmbmUCvvMB-DIk0u-6yisq891QUipOql8vpTXfNoVcb7d38_1sVUvuADlMMbz65PdQVo6k8_x-UkkfqzFhl8TJQ8qyPae94gx0pmfby3AVoK8oKUdb2JAI3EJpOX7NIxhJyYBwxh1JoxQAS2nU1cs98bV2d9tZOogsa4TS75nIUUFeRrAYtvj3MYuwx4ZB3ol-rRGEyU65Fv-3uofQwaoAOQhI9gkBQARw.5nVsPbvJ7UOG-7_-9svp2FwrIkxKxgFf7jtRflL6Y-g&dib_tag=se&keywords=pico+breadboard+kit&qid=1774489042&sprefix=pico+bread%2Caps%2C196&sr=8-1) for the breadboard
Parallax 32312 Micro SD Card adapter

The GeeekPi costs $13.59, a little more than the breadboard @granz suggested, It comes with a smaller breadboard but it has a socket for the Pico and well labeled pins to connect jumpers to. It would be a good starter for someone new to microcontrollers.

I have seen that board, but decided on the one with the LCD (GeeekPi GPIO Expansion Module (https://www.amazon.com/dp/B0C98G37PW)) instead.
(https://m.media-amazon.com/images/I/619NnEgeUFL._AC_SL1500_.jpg)

Quote from: MicroNut on Mar 25, 2026, 10:03 PMIt does have a design flaw though. The input for the onboard buzzer is left floating so when you power the Pico it usually starts buzzing unless you jumper the buzzer input to ground,

That is pretty strange as the one (actually a couple) shown above, that I have, does not have that trouble with the buzzer. ???

Quote from: MicroNut on Mar 25, 2026, 10:03 PMI did have a SD card init problem due to using the Pico's 3.3V output for the SD card. I did the suggested doubling of the ground and power jumpers and I got the SD card running so now I'm running RunCPM.

Next I'll try the emulator that Chris pointed out to see if I can use the Pico's Wifi.

Sounds good. Did you run CP/M back in the '70s/'80s?

I had a job back in 1986 that had a computer that ran CP/M. We didn't use it but during some of my down time I played Monopoly on it.

I thought about getting that Geeekboard with the LCD. The buzzer doesn't always buzz on the boards but when I connected mine to power it usually did so I have it tied to ground. It annoys my wife since my "workshop" is my side of the recliner couch with a lapboard. It drowns out the audio from the episode of Gilmore Girls she's watching :)

Quote from: granz on Mar 26, 2026, 08:09 AMI have seen that board, but decided on the one with the LCD instead.

I couldn't help but notice one thing missing from the Pico Breadboard Kit...namely, the breadboard! LOL

(https://m.media-amazon.com/images/I/619NnEgeUFL._AC_SL1500_.jpg)

That's why I didn't get it! :)  I have many Arduino TFTs I could wire up to it plus I have Pico mini LCD  module that can plug into a Pico expander that takes 5 modules.

Quote from: MicroNut on Mar 26, 2026, 09:40 AMI had a job back in 1986 that had a computer that ran CP/M. We didn't use it but during some of my down time I played Monopoly on it.

I never had much chance to play with CP/M either. Being a TRS-er (my first computer was that ZX-81, but my first "real" computer - that had disk drives and a real (not the thermal) printer was the TRS-80 Model I) I played with TRS-DOS, NewDOS and LDOS, much more than CP/M. The Model II, and IV, could run CP/M, but the Model I took some expensive hardware to run it.

Quote from: MicroNut on Mar 26, 2026, 09:40 AMI thought about getting that Geeekboard with the LCD. The buzzer doesn't always buzz on the boards but when I connected mine to power it usually did so I have it tied to ground. It annoys my wife since my "workshop" is my side of the recliner couch with a lapboard. It drowns out the audio from the episode of Gilmore Girls she's watching :)

Strange, I wonder what the difference is? I'll have to take a look at the schematics to see what they did differently in the wiring. I wonder if there is something that you can do to to the board to stop the buzzing while leaving the speaker header pin open to use? Have you tried leaving a wire connecting the speaker input to one of the GPIO pins of the Pico?

The buzzing is a strange thing. If you look at the reviews, many people had this problem and grounding it was the solution. My guess is that the board is multilayered with a power plane a ground plane. And the power plane may be too close to the buzzer trace causing the floating issue. They may have corrected it for your LCD board.

Quote from: Chris Savage on Mar 26, 2026, 10:32 AM

Quote from: granz on Mar 26, 2026, 08:09 AMI have seen that board, but decided on the one with the LCD instead.

I couldn't help but notice one thing missing from the Pico Breadboard Kit...namely, the breadboard! LOL

Yeah, I normally think that the half-sized breadboards are a bit too small (unless I am trying to design a tiny dev kit, of course. :P ) That is why I chose the one with the LCD, rather than the breadboard.

The double breadboards is one of the things that I really like about my K & H, DT-01 Digital Trainer (https://www.kandh.com.tw/dt-01-digital-trainer-dt-01.html), the Propeller Professional Development board in my Portable Workstation - Notebook (https://zappbots.altervista.org/forum/viewtopic.php?f=40&t=327) and the several Radio Shack-style breadboards (https://www.amazon.com/Makeronics-Solderless-Tie-Points-Breadboard-Prototyping/dp/B07Q34YND5).

Quote from: MicroNut on Mar 25, 2026, 10:03 PMI decided to join the fun ;D . My setup is the following: Pico WH, Parallax 32312 Micro SD Card adapter. I did the suggested doubling of the ground and power jumpers and I got the SD card running so now I'm running RunCPM. Next I'll try the emulator that Chris pointed out to see if I can use the Pico's Wifi.

So, the CP/M install doesn't require the Z80 Emulation? I guess I thought the emulator provided the Z80 capability to run the O/S AND the assembly programming.  :-\

Quote from: Chris Savage on Mar 27, 2026, 04:38 PMSo, the CP/M install doesn't require the Z80 Emulation? I guess I thought the emulator provided the Z80 capability to run the O/S AND the assembly programming.  :-\

RunCPM is an emulator, written in C, which has been ported to many different platforms (https://github.com/MockbaTheBorg/RunCPM). The version that we are reviewing here has been ported to the Raspberry Pi Pico (https://github.com/guidol70/RunCPM_RPi_Pico). It is a regular .UF2 file (object code file for the Pico,) and once installed on the Pico, turns it into a Z-80 based CP/M system. So, yes the RunCPM is, in and of itself, a Z-80 emulator. Included in that emulator is a BIOS to allow the Z-80 to read from, and write to, the SD card, and boot the CP/M included there.

One of the great things about this Pico version is that it is distributed in the .UF2 format (although you can download the source and compile it yourself with a C compiler.) The .UF2 format allows it to be simple to install. The Pico has a built-in "boot loader," where you hold down the Boot button in the Pico while plugging the USB cable into your PC. When you plug it in, it appears to your OS (Windows, Mac or Linux) as a new drive - like a thumb drive. This new "drive" has two files already on it, and you just click-and-drag the .UF2 file onto that new "drive." This copies the file to the Pico, and when the file is done copying, the new drive on your PC disappears, the Pico reboots and starts running the program in that .UF2 file. In the case of RunCPM, that program is the Z-80 emulator, along with the custom BIOS and the CP/M files on the SD card. The rest of the SD card is for hard drives, which are actually just sub-directories (folders) named A through P (for drives A: through P: - 16 drives is the maximum that CP/M can access.)

Interesting...

The last few days I've been running the RunCPM Pico emulator and the Z80 Pico emulator which runs CP/M 2.2 and here is what I found out.

RunCPM https://github.com/guidol70/RunCPM_RPi_Pico (https://github.com/guidol70/RunCPM_RPi_Pico)
This has many versions. You do need to be careful of which version to use based on your Pico. I tried the 275MHz version on a Pico W and it didn't work. The author mentioned using the 260MHz version and that worked. The latest 260MHz version is 6.7. Another thing is that when you compile the ino file for the 260MHz version it won't compile because of a mismatch error in the SDFat library it uses but the other versions compiled. I had to downgrade my Pico board version from 5.5.1 to 4.0.0 to compile it. Thankfully as @granz pointed out there is a uf2 file so there is no need to compile it.

Using the AI Codec I tried adding telnet to the code. Codec was able to add it but when I ran it the banner in the serial terminal showed WIFI is unsupported. I found creating CP/M disks was very easy to do on the SD card since the cp/m rom is built into the emulator.


Z80 Emulator https://github.com/djbottrill/rp2040_z80_emulator (https://github.com/djbottrill/rp2040_z80_emulator)
This emulator will boot into Nascom Basic if it doesn't find CPM 2.2 roms in the root directory of the SD card. If it does detect if you are using a Pico W it will start up the Telnet server Pico80.

The documentation on how to set up the SD card and use CPM is poor and at first I couldn't get it to work. With Codec I found out how to use it. It needs the rom files with a txt mapping file in the root directory, a directory /downloads with the cpm files you want to use and a /disk director with A.dsk, B.dsk... .  You need to copy the SD Card directory in GitHub into your SD card. Transferring files is a bit of a chore. There are 3 commands you need to use.

SDPATH <directory> This switches the CP/M to that directory on the SD card. It defaults to /download if not used.

SDFILES - Shows the files in SDPATH.

SDCOPY <File> Copies the file found in the SDPATH to the current dsk file the CPM is using.

This is very cumbersome. I found a bug in the CPM. When you do DIR or DIR *.* you only see DOWNLOAD COM. You must have part of the file name in the wildcard to have it show up. BTW, DOWNLOAD is a program to download serially or through Telnet a program to the disk. I haven't tried it and there is no documentation on what protocol to use.

There is just the ino source file so you do need to install Arduino and add the Pico board to compile and run it.


My take on this is if you want to introduce someone to Z80 by using a Pico, RunCPM is your best bet. It is much easier to use. I'm going to go through the source code so I can fix the mismatch, implement telnet and figure out how to configure the speed. Once I have it worked out I'll fork the project on Github.

I've been always a little leery of AI but with a long discussion with Codec I got Telnet on RunCPM working and got it updated so it will compile with the 5.5.1 version of the board. It still needs a little polishing and testing.

Quote from: MicroNut on Mar 28, 2026, 04:04 PMI've been always a little leery of AI but with a long discussion with Codec I got Telnet on RunCPM working and got it updated so it will compile with the 5.5.1 version of the board. It still needs a little polishing and testing.

Very impressive, thanks. I forget, does Telnet have up/down-load capabilities? I just checked the Telnet client that comes with Linux Mint, but the help screen did not mention anything. Do you know of a telnet client which does (and incidentally will your Telnet server for RunCPM have any file transfer built in)? I guess that we could just shell out of Telnet and use Xmodem to send/receive files - IIRC RunCPM does have Xmodem included.

Here is RunCPM (https://www.dropbox.com/scl/fi/z104b70qhonk5qeccg3ac/RunCPM_v7_0_PicoW_260Mhz_Internal-64k_03282026.zip?rlkey=g78c5zep1kvffe5nz9482b40y&st=a8b9tp5u&dl=0) with WIFI for the Pico W

This only works on the Pico W. To use edit the wifi.cfg file to have your ssid, password and optionally the hostname. If Enable is set to 0 it will use serial rather than Wifi. The fallback entries are something the AI put in and doesn't affect the operation. Now put the edited file in the root directory in the SD Card.

If you don't put wifi.cfg into the SD Card it will use the defaults in wifi_config.h file, which currently has the Enable set to 0, so serial will be used.

To compile the source use the Arduino IDE and put in the following in the Additional Boards manager
https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json
It will compile for the current version 5.5.1 and select the Pico W board.

Then using Putty or install Telnet (https://www.laptopmag.com/how-to/enable-and-use-telnet-on-windows-11) in Windows. It will use the IP assigned to the Pico and Port 23 to communicate with the Pico. For serial the baud rate is 115200. The behavior is the same regardless if it uses Telnet or serial.

@granz Telnet does not have file transfer ability. ExtraPutty (https://sourceforge.net/projects/extraputty/) can do XModem and YModem file transfers. There is xmodem80 (https://github.com/mengstr/xmodem80) that works for the esp8266. I haven't tried it but it may work. Let me know if it works.

Quote from: MicroNut on Mar 29, 2026, 06:29 PMThis only works on the Pico W.

How about the Pico 2W?

Quote from: MicroNut on Mar 29, 2026, 06:29 PMTo use edit the wifi.cfg file to have your ssid, password and optionally the hostname.

Can we give an IP address for static IP?

Quote from: MicroNut on Mar 29, 2026, 06:29 PMIf Enable is set to 0 it will use serial rather than Wifi. The fallback entries are something the AI put in and doesn't affect the operation. Now put the edited file in the root directory in the SD Card.

If you don't put wifi.cfg into the SD Card it will use the defaults in wifi_config.h file, which currently has the Enable set to 0, so serial will be used.

To compile the source use the Arduino IDE and put in the following in the Additional Boards manager
https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json
It will compile for the current version 5.5.1 and select the Pico W board.

Then using Putty or install Telnet (https://www.laptopmag.com/how-to/enable-and-use-telnet-on-windows-11) in Windows. It will use the IP assigned to the Pico and Port 23 to communicate with the Pico. For serial the baud rate is 115200. The behavior is the same regardless if it uses Telnet or serial.

@granz Telnet does not have file transfer ability. ExtraPutty (https://sourceforge.net/projects/extraputty/) can do XModem and YModem file transfers. There is xmodem80 (https://github.com/mengstr/xmodem80) that works for the esp8266. I haven't tried it but it may work. Let me know if it works.

This looks great, I'm going to give it a try tomorrow. This may change our game plan - no wiring needed.

I don't have a 2W to test but if you do try compiling it with that board selected. When I tried just the Pico board the compiler threw an error saying this board does not support Wifi. It does compile for the 2W

A static IP? I queried Chat GPT and it said it can be added to the wifi.cfg with some modifications since it looks like the Wifi API permits static IP configuration setup.

I'm busy until Tuesday then I'll look into making a 7.1 version with static ip.

Thanks, and thanks for this work that you are doing on this.

Quote from: granz on Mar 30, 2026, 05:39 AMThanks, and thanks for this work that you are doing on this.

I would like to second that sentiment. The more of us who research and share this stuff, the more people we help, even if we never know it.  ;)

Here is version 7.1 of RunCPM (https://www.dropbox.com/scl/fi/wmbda0goi39etggu48piz/RunCPM_v7_1_PicoW_260Mhz_Internal-64k_03302026.zip?rlkey=19pq2gtravlj6xw8dx9mmjp9f&st=3erascyg&dl=0)

This adds Static IP settings in wifi.cfg.

You will also notice CONNECT_TIME_OUT which is the connection timeout for the wifi (15 seconds) when it times out the FallbackAP settings will be used to make a WIFI Access Point that the your computer will connect to. Just scan the WIFI on your computer and the FALLBACK_AP_SSID will show up to connect to. If you want a password then put one in FALLBACK_AP_PASSWORD and the FALLBACK_AP_IP is the IP you connect to with Telnet using port 23

The defaults are wifi_config.h

Here's an update RunCPM (https://www.dropbox.com/scl/fi/jldlyijm9wm2rns6nfted/RunCPM_v7_1_PicoW_260Mhz_Internal-64k_04042026.zip?rlkey=opeuqdy4axzji0bu3ohbv1ezi&st=7e8womrj&dl=0)

The wifi.cfg has changed
TELNET_PORT Now you can set the port. It defaults to 23

CONNECT_TIMEOUT_MS
Negative (-1) Does not fallback into the AP Just looks for STA
0 Immediately goes to the fallback AP
xxxx timeout in milliseconds before going to the fallback AP

Has anyone tried this with the Pico 2W? Once I confirm that works I'll put it up on Github

This has been an interesting project. My workplace has recently subscribed to ChatGPt so this has been a learning experience for me. It did well on this project but the one at work I'm using it on is being very difficult. You can't rely on AI 100%.

Unfortunately, I have not been able to do anything this week (not even my hobby stuff.) On Monday, I went to the acupuncturist and after the treatment, I was in so much pain that I could not even complete my exercises or walking. When I got done, I could not even go out in the hall to get my wheelchair - the nurse had to get it for me. The whole week I could not walk around in my house without my walker - normally I will often leave it at one end of my house, and walk around without it like I did at our meetup. No more acupuncture for me.

I am just getting to be able to walk without the walker today. Hopefully I will be able to get started on some of my stuff next week.

I hope you get better soon.

Thank you. Yesterday, I was feeling much better (still not great, but better.) Today, it seems that my back has taken a step backwards. Hopefully once I get moving the pain will ease up a bit.

Feel better, granz! We need ya in good shape!  :)

Quote from: Chris Savage on Apr 05, 2026, 11:38 PMFeel better, granz! We need ya in good shape!  :)

Thanks, I am feeling much better, although yesterday was so painful that Marilyn thought that we might need to leave church before service.

This morning, I was able to do my exercises, and my morning walk, again. I had to reduce my reps to 10 (from 15 before my troubles,) but I was able to get them done. My physical therapist gave me a few more exercises on Friday, but I'm holding off on adding them for now.