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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. Just, don't actually do this mod, because then we'll make sure to tell your insurance about it, and you won't be able to collect any money after you set your house on fire with it.

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