Z80 Emulation Using the RP2040

[granz]

Got ya, sorry about taking so long. I'll get the board set up tomorrow.

[granz]

Okay, an update on pricing:
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 - $11.42 - 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 - $8.99 - https://www.amazon.com/Lerdisk-Wholesale-1GB-Produced-Authorized/dp/B0D3KWY34B
• Hookup Wire - $6.19 - https://www.amazon.com/MECCANIXITY-Breadboard-Electronics-Electronic-Projects/dp/B0F1YDQ53Q

Updated Total - $36.68 + sales tax
No shipping fee for Prime Members.

Next post - steps to assemble the system.

[Chris Savage]

Next post - steps to assemble the system.

Will this work with the original parts I bought for both of us?

[granz]

Will this work with the original parts I bought for both of us?

Yes.

Although, I did get the RP2040-GEEK to work, and it is less than half the price (only $16.31 from Amazon - https://www.amazon.com/RP2040-GEEK-Development-Raspberry-Microcontroller-Downloader/dp/B0CG82MKWC.) The only thing that would need to be added would be the micro SD Card.

This would also eliminate the need to wire the thing up (and also eliminate the possibility of mistakes in wiring.)

The only thing remaining for this is for me to figure out how to work with .DSK files so that I can remove the extraneous stuff, and add the editor and assembler/linker.

So, I am also continuing work on the RP2040-GEEK version, in addition to the original.

[granz]

Setting up the hardware

This is the pinout of the Raspberry Pi Pico:


Step 1:

Start by inserting the Raspberry Pi Pico into the breadboard. You will need to press pretty firmly to get the Pico to seat all the way to the breadboard. Be careful to avoid pressing on the Pico's pins - the can hurt your fingers.

Step 2:

Next insert the SD card breakout into the breadboard, as shown. Don't insert the SD card into the socket before you put the breakout into the breadboard as you will need to add the CP/M files in the Software step.

Step 3:

Take a close look at the pin labels on the breakout. You should notice that they are, from left to right:

• GND - Ground
• VCC - +Voltage
• MISO - Master In Slave Out
• MOSI - Master Out Slave In
• SCK - System Clock
• CS - Card Select

If you are using a different SD card breakout, you will need to verify the pinout of the breakout and adjust these directions per your card.

Step 4:

In wiring up the SD card breakout, start off with the power connections. Connect a black jumper to pin 38 of the Pico module. Then connect the other end of that jumper to the left-most pin of the breakout. Use a red jumper to connect pin 36 of the Pico to the next breakout pin to the right. These will provide the power required for your SD card. Only four more to go.

Step 5:

Use different colored jumpers to connect up the rest of the SD card breakout.

Going from the red VCC pin on the breakout board, going right:

• MISO - Pico pin 21 (white)
• MOSI - Pico pin 25 (yellow)
• CS - Pico pin 22 (blue)
• SCK - Pico pin 24 (orange)

The colors listed are the colors that I used, you may use whatever colors are convenient to your board. Try to avoid black, and red, as those are the standard colors for power connections.

Next, we install the RunCPM firmware, and then set up the CP/M files in the Software step.

Edited to add Pico pinout at top of post.