Pi Pico)¶

PlayStation 1 / PlayStation 2 controllers to USB HID gamepad. Auto-detects digital pads, DualShock, DualShock 2 (with pressure), neGcon, Dual Analog flightstick, GunCon, JogCon, and PlayStation Mouse.

Parts Needed¶

One of:
Adafruit QT Py RP2040 (~$10)
Adafruit KB2040 (~$10)
Raspberry Pi Pico (~$4)
PlayStation controller extension cable (cut to expose wires), or a salvaged PSX/PS2 console-side socket
One 1 kΩ to 10 kΩ resistor (pull-up on DAT)
Hookup wire (22–26 AWG), soldering iron

PSX Controller Connector¶

The PSX/PS2 controller plug is 9-pin. Looking into the console-side socket (or at the back of a cut extension cable):

  _________________________
 |   1   2   3 | 4   5   6 | 7   8   9   |
  \__|___|___|_|_|___|___|_|_|___|___|__/

 1 = DAT  (data from controller, open-drain)     6 = ATT  (attention / chip select, active-low)
 2 = CMD  (commands to controller)               7 = CLK  (clock, ~250 kHz - 500 kHz)
 3 = +7V  (rumble motor power, OPTIONAL)         8 = (not connected for slot 1)
 4 = GND                                         9 = ACK  (acknowledge, not required)
 5 = +3.3V (controller logic power)

Pin 3 (+7V) only matters if you want rumble on a DualShock — wire it to a separate 7.5 V supply not through the MCU. Do not wire pin 3 to a USB 5 V rail; the rumble motors brown-out the controller and corrupt analog reads.

Wiring¶

The active-pull-up PIO needs CLK and ATT on consecutive GPIOs (it's a 2-bit side-set with CLK on the lower pin). The other two lines can be on any free pin. Per-board pin assignments:

QT Py RP2040 (primary target)¶

⚠️ The QT Py RP2040 numbers its analog pads in descending GPIO order — A0 is GP29, A3 is GP26 (the reverse of the KB2040). Wire by the pad label in the table below, not by assuming A0 is the lowest GPIO.

QT Py pad	GPIO	PSX Pin	Signal
A0	GP29	1	DAT
A1	GP28	2	CMD
A2	GP27	6	ATT
A3	GP26	7	CLK
3V	—	5	+3.3V
GND	—	4	GND

KB2040¶

Same GPIOs as the QT Py (CLK=GP26, ATT=GP27, CMD=GP28, DAT=GP29), but the KB2040 numbers its A0–A3 pads in ascending GPIO order (A0 is GP26), so the pad labels are the reverse of the QT Py.

KB2040 pad	GPIO	PSX Pin	Signal
A0	GP26	7	CLK
A1	GP27	6	ATT
A2	GP28	2	CMD
A3	GP29	1	DAT
3.3V	—	5	+3.3V
GND	—	4	GND

Raspberry Pi Pico¶

Pico GPIO	PSX Pin	Signal
GP20	7	CLK
GP21	6	ATT
GP19	2	CMD
GP22	1	DAT
3V3 OUT	5	+3.3V
GND	4	GND

Pull-up on DAT¶

DAT is open-drain; the controller pulls it low for 0 bits and lets it float for 1. The RP2040's internal pull-up works for most modern pads, but old analog pads (e.g. Sony SCPH-110) read cleaner with an external 1 kΩ to 10 kΩ resistor from DAT to +3.3V. The firmware's active-pull-up PIO trick handles the rest.

Build and Flash¶

# Build
make psx2usb_qtpy            # or psx2usb_kb2040 / psx2usb_pico

# Flash: hold BOOTSEL while connecting USB
make flash-psx2usb_qtpy      # or psx2usb_kb2040 / psx2usb_pico

Output file: releases/joypad_<commit>_psx2usb_<board>.uf2 (a local build is tagged with the short commit hash; release builds are tagged with the version instead, e.g. joypad_2.4.0_psx2usb_qtpy.uf2).

ℹ️ There is no prebuilt UF2 to download yet. psx2usb was only added to the release build matrix on 2026-08-05, after v2.3.0 shipped — no release up to and including v2.3.0 contains a psx2usb asset. Until the next release, building from source with the commands above is the only way to get this firmware.

Testing¶

Wire the adapter per the table above.
Plug the adapter into a PC via USB.
The board enumerates as a Joypad SInput controller by default.
Plug a PSX controller into the cable. Open a gamepad tester (gamepad-tester.com, or joypad.ai, which reads the pad over WebHID and therefore works in any output mode) and verify:
Digital pad — all 12 face/d-pad/shoulder buttons + Select/Start register.
DualShock — both analog sticks center near 128, L3/R3 click, ANALOG button toggles modes (a brief A1/Guide press fires on each toggle).
DualShock 2 — per-button pressure visible in the PS3-mode pressure view.

⚠️ config.joypad.ai is the configuration tool, not the tester, and it needs the USB serial (CDC) interface. CDC is only present in the SInput (default), Keyboard/Mouse and CDC-only configuration descriptors. Cycle the adapter to XInput, PS3, PS4 or Switch and the CDC interface disappears from the descriptor, so config.joypad.ai can no longer see the board — triple-click BOOTSEL to return to SInput before configuring.

Output Modes¶

The adapter ships in SInput mode (the default — full feature set, recognized by Steam/SDL). Double-click the BOOTSEL button to cycle output modes: SInput → XInput → PS3 → PS4 → Switch → Keyboard/Mouse → …; triple-click resets to SInput.

Single press of BOOTSEL emits A1 (Guide/PS button) while held — useful for navigating console home menus or triggering a PS-button init without a Select+Start combo.

PS3 mode emits an authentic DS3 descriptor (works on real PS3 consoles).

Status LED — board-dependent¶

The mode colour is driven through leds_set_color(), which only ever reaches a NeoPixel. What you see depends on the board:

Board	Status LED	Mode colour shown?
QT Py RP2040	NeoPixel on GP12 (powered from GP11, driven high at init)	✅ yes
KB2040	NeoPixel on GP17	✅ yes
Raspberry Pi Pico	none	❌ no

⚠️ The Pi Pico build has no status LED at all. The Pico has no NeoPixel, and the psx2usb target never defines BOARD_LED_PIN, so the plain GP25 LED is not driven either — neopixel_init() compiles down to an immediate return and leds_set_color() has nothing to write to. Mode switches on a Pico are completely silent; confirm the active mode from the USB device name on the host instead of looking for a light.

On the two NeoPixel boards the colours are: white = SInput, green = XInput, blue = PS3/PS4 (dim/bright), red = Switch, yellow = KB/Mouse.

Controller-side combos¶

These come from the shared USB-device layer and are not documented elsewhere for this adapter:

Select + Start → A1 (Guide/PS) — only on genuine digital-only pads. DualShock-family pads (DualShock, DS2-pressure, Dual Analog flight) reach A1 through their physical ANALOG button, so their Start+Select is deliberately left intact — otherwise output modes with no A1 (e.g. Xbox Original) would lose the ability to press the two together.
Select (hold ~2 s) + D-pad Up/Down — cycle button profiles.
Pads with no Select button — the Dual Analog flight stick (0x53), GunCon and PlayStation Mouse — therefore cannot reach either combo. Use BOOTSEL for A1 on those.

Supported Devices¶

Device	Type ID	Notes
Digital pad (SCPH-1080)	0x41	Standard 12-button pad
DualShock	0x73	Analog sticks auto-enabled
DualShock 2	0x79	+ 12-byte per-button pressure
neGcon	0x23	Namco NPC-101; twist + I/II/L analog
Dual Analog flight	0x53	SCPH-1110 / Dual Analog "red" mode
GunCon	0x63	Namco light gun; aim on right stick (needs CRT)
JogCon	0xE3	Namco paddle wheel on left-stick X
PlayStation Mouse	0x12	SCPH-1090; relative cursor + 2 buttons

Notes¶

No CPU overclock required (standard 125 MHz).
ANALOG button → A1/Guide is detected via the analog ↔ digital mode toggle; it fires a brief A1 pulse on every press so a console PS-button init still registers.
Rumble motor bytes are pulled from the active output's feedback state each poll (heavy/low motor → the large PWM byte, light/high motor → the small on/off byte), so any output mode that reports rumble drives them. The motors only respond after the pad's 0x4D enable-rumble mapping has been sent, which happens during DualShock configuration. A JogCon is excluded — it drives the same two motor bytes itself for the wheel force-feedback recentre, not host rumble. The 7.5 V motor rail must be supplied externally (NOT through the QT Py / KB2040 / Pico).
See PSX input docs for protocol details (SIO bus, active pull-up, controller ID layout).
See psx2usb app docs for feature details + USB output mode list.