PSXVX
Memory card backup
Posted on: Feb 15, 2019 3:41 PM UTC
I recently found my old PS1 memory cards and wondered how to retrieve the data on a computer so that I can use the saves in emulators.
Memory card hardware
A memory card has 8 connections, all of them are linked to the corresponding ones of the controller in the same port.
Data = grey, Command = purple, etc.
There is the power supply:
VCC, GND, +7V (rumble).The Acknowledge (
/ACK) port is for the device to send an acknowledgement command after having received a byte.Then Data (
MISO), Command (MOSI), Attention (CS) and Clock (SCK) are standard SPI.Software
The communication protocol described in https://problemkaputt.de/psx-spx.htm#controllerandmemorycardioports is pretty trivial.
Shendo even created a program to flash to an AVR that talks to memory cards and a Python script that talks to this program.
I had to adapt the
.ino (C file to used with the Arduino software) program for the ATmega8535 I used for this task and I also changed the Python script to better take errors into account.I'll publish these in my PS1 software repo but in the mean time the Shendo's files works perfectly.
Making it
I removed the controller/memcard block from the PS1 and soldered wires as in the first image of this article.
MISO, MOSI, CS and SCK were connected to the ATmega8535 as expected, /ATT is optional and was left alone.Also it looks like the
+7V port can be connected to a 3.3V source (both with Sony memcards and third party memcards).I used a Raspberry Pi to control the AVR chip (through RX/TX) but any UART-capable computer would work.
And finally it's quite easy to make it work using the serial port to the chip.
$ python memcarduino.py -p /dev/serial0 -r memcard.mcr
running mcduino check
passed mcduino check
Running mcr header check MCDINO
Sending... \xa20001
Reading 129bytes...
passed header check
reading data from memory card...
OK at frame 1/1024 Address:00 00 TimeTaken:0:00:00.225765
OK at frame 2/1024 Address:00 01 TimeTaken:0:00:00.225847
OK at frame 3/1024 Address:00 02 TimeTaken:0:00:00.225859
[...]
OK at frame 1024/1024 Address: 03 FF TimeTaken:0:00:00.225482
SUCCESS Then you can use your
*.mcr files as virtual memory cards in emulators and use them as you want.References
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