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USB to Serial PSX cable

This cable connects a PSX to a computer.

You can then interact with the following to upload/download binary data, peek/poke, hook r/w/x, launch executables, etc...

  • Unirom booted from a cheat cart
  • Unirom booted from a memory card
  • Unirom booted from a CD

Suitable USB/Serial adapters :

If you have this stuff lying around, this can help :

  • A PSX SCPH-1040 serial cable, or half a cable
  • A dead PSX motherboard that has a serial port, or just the SIO socket
  • Dupont wires
  • Component AV Multi Out cable

Connection

You only need 3 wires from the PSX : Tx, Rx and Gnd.

PSX pins | FTDI pins
2        |     GND   
8        |     TX 
5        |     RX 

Which controller can be used

FTDI FT232RL

Connect PSX SIO pins 2, 5, 8 to the FTDI's Tx, Rx and Gnd. Done.

FTDI to PSX

3.3V Arduino Uno

Some arduino unos have a jumper to use 3.3V instead of 5V levels. You can use such a board with an additional resistor, like so :

Arduino 3.3V

Sources : http://www.psxdev.net/forum/viewtopic.php?f=47&t=760&p=19081

Raspberry Pi

Either over your local network or via a direct lan cable setup, you can use a rpi if you have one lying around.

Plug the PSX's serial output Rx/TX/Gnd to the GPIO14/pin 8 (Tx), GPIO15/pin 10 (Rx) and pin 6 (Gnd).

RPI to PSX serial connection

See here for the full solution : http://wiki.arthus.net/?psxdev-rpi_serial_over_network

Raspberry Pi Pico

The new controller by Rpi foundation can be used to with the Pico-uart-bridge firmware :
https://github.com/Noltari/pico-uart-bridge/releases

Use GPO 0/Pin 1 as Tx, GPO 1/Pin 2 as Rx and GPO 3/Pin 3 as Gnd :

Rpi pico pinout

CP2102 / CP2104

The CP2102 and CP2104 are reported to work at least in /slow mode (115200 bauds).

Rpi pico pinout

Others :

  • CH341 is reported to work in /slow mode (115200 bauds)

From the PSX to the controller

Method #1 : Half SCPH-1040 cable

Hack the cable, connect things and voila :

SCPH-1040

Sources : http://www.psxdev.net/forum/viewtopic.php?f=62&t=349#p2592
http://www.psxdev.net/forum/viewtopic.php?t=497#p3556

Method #2 : Salvaged PSX serial port + full SCPH-1040 cable

Use a salvaged PSX SIO port from a dead motherboard, and use your precious serial cable without destroying anything :

Serial port

Serial port

Source : http://www.psxdev.net/forum/viewtopic.php?t=744&sid=ff1cc884ceaaa4267404e61e81130320#p6524

Method #3 : Dead or spare PSX motherboard + full SCPH-1040 cable

Same as above except you don't even have to hack the SIO port off the motherboard, just solder your wires directly underneath the SIO port.

Serial motherboard

Sources : https://thp.io/2020/psxserial.html

Method #4 : Component AV Multi Out cable adaptor to serial I/O

Component AV Multi Out cables contains all 12 pins; cutting the extra plastic of a component AV Multi Out Cable makes it fit perfectly on the Playstation's serial I/O port. The extra pins sits open within the serial I/O port.

A photo displaying how it looks like when connected: AV Multi Out adaptor to serial I/O with extra plastic cut

One may cut the extra borders of the metal case with a mini saw blade, leaving a bit of base for it's lower part to remain connected; here is a photo displaying how it looks like with it on: AV Multi Out adaptor to serial I/O with metal case cut

A photo displaying how it looks like, when connected with it's AV Multi Out enclosure: AV Multi Out adaptor to serial I/O connected with it's original enclosure on

A photo displaying the adaptor dowside-up: AV Multi Out adaptor to serial I/O downside-up

Source : Anonymous

Sources

PSX Serial port pinout

Method #1a
Method #1b

Method #2

Method #3

Method #4