Recently, when I was clearing out some things from my parent’s house, I came across my old Sony PSP. I have a lot of fond memories playing games like Patapon 2, Wipeout, and Metal Gear Solid on the thing, so I thought it would be fun to revisit some of those games. Problem is, I’d rather play them on a TV! While the PSP 2000 I have supports video out, there is no way to use a real controller, so you’re stuck with the built-in tiny joystick. Unless… I could create an adapter to enable me to use a Playstation 2 controller!

PS2PSP

While I initially wanted to create an adapter to let me use the original PSP controls, in addition to the PS2 controller, I quickly realized this would increase the amount of work needed by quite a bit. To make that happen, I would have to create flat-flex cable (FFC) adapters that could splice the original FFC and my new cables together, or attempt very difficult micro-soldering to bypass the cable connectors entirely. Thus, I decided to create a “consolized” PSP! I stripped the PSP down to its motherboard, and designed my circuit board to handle the PS2 to PSP conversion and power delivery.

PS2PSP Front

PS2PSP Back

The core of the board is an ATmega328 microcontroller. This is connected to the PSP through three ribbon cables - one for the directional pad and left trigger, one for the face buttons and right trigger, and one for start, select, and other function buttons. Triggering a button is simple with the microcontroller - just pull the appropriate signal to ground.

To replace the joystick on the PSP, I added a two-channel digital potentiometer chip to the PCB. This chip is connected to the microcontroller through I2C, a simple two wire communication protocol. Using this chip, I’m able to control the X and Y axis of the PSP joystick with 256 bit resolution.

With those elements in place, it becomes relatively simple to map the PS2 controller to the PSP controls. The PS2 controller’s second analog stick can be mapped to the PSP face buttons, enabling psuedo-analog control for quite a few PSP games.

The design is open source, and available here.