AVR PSX Controller Library
Here is a simple PSX Controller library which I wrote / adapted for generic AVR use. I loosely based it on Bill Porter's Arduino library, with many changes to bring it closer to the spec reverse engineered from CuriousInventor Tutorials and Micah Dowty's protocol notes.
This is currently licensed for personal use only, although I plan on releasing it (along with my other AVR libraries) under a CC license, pending approval from the people various library components are based off of. Check back for updates, or email me if you have questions.
psx.c:
/******************************************************************
* PS2 controller library for AVR
*
* Loosly based off of code by Shutter on Arduino Forums, and modified
* (added analog stick support) by Bill Porter (http://www.billporter.info/?p=219)
*
* Converted to generic AVR library without C++ or Arduino references, added
* the ability to use any pins for input / output, fixed numerous bugs, actually
* follow proper PS2 controller protocols, etc by Wyatt Olson (http://digitalcave.ca)
*
* Thanks to http://store.curiousinventor.com/guides/PS2/#high_level for protocol details.
*
* Lib version history
* ???? 0.1 Bill Porter -Made into Arduino library
* -Added analog stick support
* 2010-07 0.2 Wyatt Olson -Converted to generic AVR-GCC library
* -Added port / pin initializers (psx_init())
* -Changed to use uintx_t data types instead of char
* -Fixed many bugs (including glaring protocol violations)
* -Code cleanup
* 2011-04 0.3 Wyatt Olson -Fixed a number of logic bugs, where the impl did not match spec
* -Code cleanup (merged methods, fixed comments, etc)
*
*
* Usage information:
* Connect PSX controller wires to AVR:
* Brown: Data
* Blue: Clock
* Orange: Command
* Yellow: Attention
* Call psx_init() function with the port / pins which you are using
* Call psx_read_gameport() regularly to poll and update.
* Call psx_button() function with PSB_X argument to read the value of the given button (see
* psx.h for possible buttons, e.g. PSB_SELECT, PSB_L3, PSB_PAD_UP, etc)
* Call psx_stick() function with PSS_X argument to read the analog stick value (possible
* values are PSS_RX, PSS_RY, PSS_LX, PSS_LY for right / left and X / Y)
*
******************************************************************/
#include "psx.h"
//Define ports used
static volatile uint8_t *_data_port;
static volatile uint8_t *_clock_port;
static volatile uint8_t *_command_port;
static volatile uint8_t *_attention_port;
//Define the input
static volatile uint8_t *_data_in;
//Define ddr used
static volatile uint8_t *_data_ddr;
static volatile uint8_t *_clock_ddr;
static volatile uint8_t *_command_ddr;
static volatile uint8_t *_attention_ddr;
//Define pins to use
static uint8_t _clock_pin;
static uint8_t _command_pin;
static uint8_t _attention_pin;
static uint8_t _data_pin;
//Common structure for last read data
static uint8_t _data[21];
/* Private. The actual serial transfer. Handles clock. The PSX controller is full
* duplex, so this will send a byte as well as receive one.
*/
uint8_t _psx_gamepad_shift(uint8_t transmit_byte) {
uint8_t received_byte = 0;
for(uint8_t i = 0; i < 8; i++) {
//Drop the clock...
*_clock_port &= ~_BV(_clock_pin);
//...set the command (outgoing) pin...
if (transmit_byte & (_BV(i))) {
*_command_port |= _BV(_command_pin);
}
else {
*_command_port &= ~_BV(_command_pin);
}
//...wait half the clock cycle...
_delay_us(CTRL_CLK);
//...raise the clock to HIGH...
*_clock_port |= _BV(_clock_pin);
//...at which point you read the data...
if(*_data_in & _BV(_data_pin)) {
received_byte |= _BV(i);
}
//...and wait the other half of the clock cycle
_delay_us(CTRL_CLK);
}
//Clock should already be high at this point, but just to be sure...
*_clock_port |= _BV(_clock_pin);
return received_byte;
}
/* Private. Sends a command using the shift method.
*/
void _psx_send_command(uint8_t send_data[], uint8_t size){
//Before you submit each command packet, you must set attention low; once
// you are done each packet, return it high. You have to toggle the line before
// you submit another command.
*_attention_port &= ~(_BV(_attention_pin));
*_command_port |= _BV(_command_pin);
//Clock should always be high; it is an active low line...
*_clock_port |= _BV(_clock_pin);
for (uint8_t i = 0; i < size; i++){
send_data[i] = _psx_gamepad_shift(send_data[i]);
}
*_attention_port |= _BV(_attention_pin);
}
/* Reads the gamepad. You need to call this whenever you want updated state.
*/
void psx_read_gamepad() {
_data[0] = 0x01;
_data[1] = 0x42;
for (uint8_t i = 2; i < 21; i++){
_data[i] = 0x00;
}
_psx_send_command(_data, 21);
}
/* Initialize the pins, and set the controller up to the correct mode. This must be called
* before any other psx_* functions are called.
* (TODO: separate the config options into optional functions, and call based on flags,
* to allow calling programs to determine what options to use)
*
* Note: We extrapolate the DDR and PIN registers based off of the associated PORT
* register. This assumes that the DDR and PIN registers come directly after the PORT
* equivalents, with DDRX at the next address after PORTX and PINX coming at the next
* address after DDRX. This is valid for all the chips I have looked at; however, it is
* highly recommended that you check any new chips which you want to use this library with.
*/
void psx_init(volatile uint8_t *data_port, uint8_t data_pin,
volatile uint8_t *clock_port, uint8_t clock_pin,
volatile uint8_t *command_port, uint8_t command_pin,
volatile uint8_t *attention_port, uint8_t attention_pin){
//Store the ports...
_data_port = data_port;
_clock_port = clock_port;
_command_port = command_port;
_attention_port = attention_port;
//... and data direction registers...
_data_ddr = data_port - 0x1;
_clock_ddr = clock_port - 0x1;
_command_ddr = command_port - 0x1;
_attention_ddr = attention_port - 0x1;
//... and data input register...
_data_in = data_port - 0x2;
//... and pin numbers.
_clock_pin = clock_pin;
_command_pin = command_pin;
_attention_pin = attention_pin;
_data_pin = data_pin;
//Set clock, attention, and command pins to output mode
*_clock_ddr |= _BV(_clock_pin);
*_attention_ddr |= _BV(_attention_pin);
*_command_ddr |= _BV(_command_pin);
//Set data pin to input mode, and set pullup resistor
*_data_ddr &= ~(_BV(_data_pin));
*_data_port |= _BV(_data_pin);
//Initialize game pad
*_clock_port |= _BV(_clock_pin);
*_command_port |= _BV(_command_pin);
//Init by polling once
psx_read_gamepad();
//Enter Config Mode
uint8_t enter_config_command[] = {0x01, 0x43, 0x00, 0x01, 0x00};
_psx_send_command(enter_config_command, 5);
// Lock to Analog Mode on Stick
uint8_t lock_analog_mode_command[] = {0x01, 0x44, 0x00, 0x01, 0x03, 0x00, 0x00, 0x00, 0x00};
_psx_send_command(lock_analog_mode_command, 9);
//Exit config mode
uint8_t exit_config_command[] = {0x01, 0x43, 0x00, 0x00, 0x5A, 0x5A, 0x5A, 0x5A, 0x5A};
_psx_send_command(exit_config_command, 9);
}
uint16_t psx_buttons() {
uint16_t buttons = *(uint16_t*)(_data + 3); //Get 2 bytes, comprising data positions 3 and 4.
return ~buttons;
}
uint8_t psx_button(uint16_t button) {
uint16_t buttons = psx_buttons();
return ((buttons & button) > 0);
}
uint8_t psx_stick(unsigned int stick) {
return _data[stick];
}
psx.h:
#ifndef PSX_lib_h
#define PSX_lib_h
#include <avr/io.h>
#include <util/delay.h>
//Half a clock cycle; 10µs seems to be about right
#define CTRL_CLK 10
//These are our button constants
#define PSB_SELECT 0x0001
#define PSB_L3 0x0002
#define PSB_R3 0x0004
#define PSB_START 0x0008
#define PSB_PAD_UP 0x0010
#define PSB_PAD_RIGHT 0x0020
#define PSB_PAD_DOWN 0x0040
#define PSB_PAD_LEFT 0x0080
#define PSB_L2 0x0100
#define PSB_R2 0x0200
#define PSB_L1 0x0400
#define PSB_R1 0x0800
#define PSB_TRIANGLE 0x1000
#define PSB_CIRCLE 0x2000
#define PSB_CROSS 0x4000
#define PSB_SQUARE 0x8000
//These are stick values
#define PSS_RX 5
#define PSS_RY 6
#define PSS_LX 7
#define PSS_LY 8
/* Initialize the controller, specifying which port and pins to use for each connection.
* We extrapolate the DDR register from the PORT register for each connection.
*/
void psx_init(volatile uint8_t *data_port, uint8_t data_pin,
volatile uint8_t *clock_port, uint8_t clock_pin,
volatile uint8_t *command_port, uint8_t command_pin,
volatile uint8_t *attention_port, uint8_t attention_pin);
/* Returns the current state of all 16 buttons */
uint16_t psx_buttons();
/* Returns non-zero if the given button is pressed. */
uint8_t psx_button(uint16_t);
/* Returns the value of the given analog stick (0-255) */
uint8_t psx_stick(unsigned int);
/* Updates the current value of the game pad. */
void psx_read_gamepad();
#endif