Z80 Emulation Using the RP2040

[MicroNut]

Here's an update RunCPM

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%.

[granz]

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.

[MicroNut]

I hope you get better soon.

[granz]

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.

[Chris Savage]

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

[granz]

Feel 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.

[granz]

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.

I now have one of the RP2350-GEEK devices, from Amazon, on its way - should be here Friday.

It appears that the RP2040-GEEK (https://www.amazon.com/dp/B0CGLBLQ43) device is actually cheaper ($17.39 w/ S&H + SD card,) than the above kit. This will be cheaper, easier and faster for a complete beginner than the kit that I sourced out.

One of the RP2040-GEEK modules is now on order (unfortunately long shipping time - 1 May - 11 May. ) I will install the RunCPM for that module when it arrives.

There is one other option that I have been considering. The Adafruit Feather RP2040 Adalogger (https://www.adafruit.com/product/5980) with a cheap 512 MB SD card is only $19.90. The shipping to my place, near Pittsburgh) is (USPS - Ground Advantage) $5.53. This would be just over $25 delivered (here.) That would cover everything in the above kit, except for the SD card - the same as the RP2040-GEEK. The -GEEK module wins by being a bit cheaper and by including a case (plus the LCD, but that would not be used for this project.) The Adalogger should get delivered sooner - Adafruit is pretty good about shipping in my experience.

Sorry about being slow on this, the pain has been pretty bad lately. I could not even get to church this past Sunday, and I was the scheduled deacon for reading the Scripture and praying. This pain is a pain.   

[granz]

I found another GitHub project that emulates the Z80 on the Pico https://github.com/udo-munk/RP2xxx-GEEK-80 It uses a WaveshareRP2040-GEEK such as 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.

Well, I received my RP2040-GEEK the other day (still have so much pain most days, that I have trouble focusing.) This morning I got the RunCPM loaded onto it. When I start the simulator running, nothing happens. I have not been able to get to a CP/M prompt. The display does show activity (several different display possibilities: registers, disks, classic LED front panel, etc. - very cool,) but unable to get to the O/S prompt.

@MicroNut , when I asked if you had one of these, you mentioned that you may be getting one of these:

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.

Did you ever get one of the RP2040-GEEK units? And, were you able to get RunCPM working? I even tried connecting to the next enumerated comm port (/dev/ttyACM1 - when the control comm port is /dev/ttyACM0,) but got nothing on that port.

The price for this RP2040-GEEK is a bit better than the breadboard unit, plus much simpler to assemble. Also, it just looks so cool. I would really like to get this CP/M Programming project working. So, I'll try some more, but I'll also try to get back to the breadboard setup in a few days.

[MicroNut]

No, I don't got the RP2040-Geek. It may be awhile before I get one. I have way too many toys to distract me so I decided to just focus on one of type of boards I've had for quite awhile, my FPGA boards.

[granz]

Got it, okay.

It is looking like the .dsk files on Udo's Github may be bad. The simulator program itself seems to be working, but it won't let me boot - I keep getting an error and it shuts down. I saw a video of this running on a regular Pico, and when he loads the disk file, and then boots, it come up in CP/M.

I'll keep looking into it - it will be a cheaper, easier way to get started in CP/M. And, if I can get a decent .dsk file created we can use this for the learning Z-80 assembly programming.

That said, the development work in getting RunCPM going on the plain Pico is really simple, and even easier on the PicoCalc. I also like the idea of running the disk straight from the SD card, rather than the .dsk image file. It's just the development work to get it going on the RP2040-GEEK that is turning into a bear.