114 lines
2.8 KiB
C
114 lines
2.8 KiB
C
|
/*
|
||
|
|
* piNes.c:
|
||
|
|
* Driver for the NES Joystick controller on the Raspberry Pi
|
||
|
|
* Copyright (c) 2012 Gordon Henderson
|
||
|
|
***********************************************************************
|
||
|
|
* This file is part of wiringPi:
|
||
|
|
* https://projects.drogon.net/raspberry-pi/wiringpi/
|
||
|
|
*
|
||
|
|
* wiringPi is free software: you can redistribute it and/or modify
|
||
|
|
* it under the terms of the GNU Lesser General Public License as
|
||
|
|
* published by the Free Software Foundation, either version 3 of the
|
||
|
|
* License, or (at your option) any later version.
|
||
|
|
*
|
||
|
|
* wiringPi is distributed in the hope that it will be useful,
|
||
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
|
|
* GNU Lesser General Public License for more details.
|
||
|
|
*
|
||
|
|
* You should have received a copy of the GNU Lesser General Public
|
||
|
|
* License along with wiringPi.
|
||
|
|
* If not, see <http://www.gnu.org/licenses/>.
|
||
|
|
***********************************************************************
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <wiringPi.h>
|
||
|
|
|
||
|
|
#include "piNes.h"
|
||
|
|
|
||
|
|
#define MAX_NES_JOYSTICKS 8
|
||
|
|
|
||
|
|
#define NES_RIGHT 0x01
|
||
|
|
#define NES_LEFT 0x02
|
||
|
|
#define NES_DOWN 0x04
|
||
|
|
#define NES_UP 0x08
|
||
|
|
#define NES_START 0x10
|
||
|
|
#define NES_SELECT 0x20
|
||
|
|
#define NES_B 0x40
|
||
|
|
#define NES_A 0x80
|
||
|
|
|
||
|
|
|
||
|
|
#define PULSE_TIME 25
|
||
|
|
|
||
|
|
// Data to store the pins for each controller
|
||
|
|
|
||
|
|
struct nesPinsStruct
|
||
|
|
{
|
||
|
|
unsigned int cPin, dPin, lPin ;
|
||
|
|
} ;
|
||
|
|
|
||
|
|
static struct nesPinsStruct nesPins [MAX_NES_JOYSTICKS] ;
|
||
|
|
|
||
|
|
static int joysticks = 0 ;
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* setupNesJoystick:
|
||
|
|
* Create a new NES joystick interface, program the pins, etc.
|
||
|
|
*********************************************************************************
|
||
|
|
*/
|
||
|
|
|
||
|
|
int setupNesJoystick (int dPin, int cPin, int lPin)
|
||
|
|
{
|
||
|
|
if (joysticks == MAX_NES_JOYSTICKS)
|
||
|
|
return -1 ;
|
||
|
|
|
||
|
|
nesPins [joysticks].dPin = dPin ;
|
||
|
|
nesPins [joysticks].cPin = cPin ;
|
||
|
|
nesPins [joysticks].lPin = lPin ;
|
||
|
|
|
||
|
|
digitalWrite (lPin, LOW) ;
|
||
|
|
digitalWrite (cPin, LOW) ;
|
||
|
|
|
||
|
|
pinMode (lPin, OUTPUT) ;
|
||
|
|
pinMode (cPin, OUTPUT) ;
|
||
|
|
pinMode (dPin, INPUT) ;
|
||
|
|
|
||
|
|
return joysticks++ ;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* readNesJoystick:
|
||
|
|
* Do a single scan of the NES Joystick.
|
||
|
|
*********************************************************************************
|
||
|
|
*/
|
||
|
|
|
||
|
|
unsigned int readNesJoystick (int joystick)
|
||
|
|
{
|
||
|
|
unsigned int value = 0 ;
|
||
|
|
int i ;
|
||
|
|
|
||
|
|
struct nesPinsStruct *pins = &nesPins [joystick] ;
|
||
|
|
|
||
|
|
// Toggle Latch - which presents the first bit
|
||
|
|
|
||
|
|
digitalWrite (pins->lPin, HIGH) ; delayMicroseconds (PULSE_TIME) ;
|
||
|
|
digitalWrite (pins->lPin, LOW) ; delayMicroseconds (PULSE_TIME) ;
|
||
|
|
|
||
|
|
// Read first bit
|
||
|
|
|
||
|
|
value = digitalRead (pins->dPin) ;
|
||
|
|
|
||
|
|
// Now get the next 7 bits with the clock
|
||
|
|
|
||
|
|
for (i = 0 ; i < 7 ; ++i)
|
||
|
|
{
|
||
|
|
digitalWrite (pins->cPin, HIGH) ; delayMicroseconds (PULSE_TIME) ;
|
||
|
|
digitalWrite (pins->cPin, LOW) ; delayMicroseconds (PULSE_TIME) ;
|
||
|
|
value = (value << 1) | digitalRead (pins->dPin) ;
|
||
|
|
}
|
||
|
|
|
||
|
|
return value ^ 0xFF ;
|
||
|
|
}
|