3 * Driver for the NES Joystick controller on the Raspberry Pi
4 * Copyright (c) 2012 Gordon Henderson
5 ***********************************************************************
6 * This file is part of wiringPi:
7 * https://projects.drogon.net/raspberry-pi/wiringpi/
9 * wiringPi is free software: you can redistribute it and/or modify
10 * it under the terms of the GNU Lesser General Public License as
11 * published by the Free Software Foundation, either version 3 of the
12 * License, or (at your option) any later version.
14 * wiringPi is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with wiringPi.
21 * If not, see <http://www.gnu.org/licenses/>.
22 ***********************************************************************
29 #define MAX_NES_JOYSTICKS 8
31 #define NES_RIGHT 0x01
35 #define NES_START 0x10
36 #define NES_SELECT 0x20
43 // Data to store the pins for each controller
47 unsigned int cPin, dPin, lPin ;
50 static struct nesPinsStruct nesPins [MAX_NES_JOYSTICKS] ;
52 static int joysticks = 0 ;
57 * Create a new NES joystick interface, program the pins, etc.
58 *********************************************************************************
61 int setupNesJoystick (int dPin, int cPin, int lPin)
63 if (joysticks == MAX_NES_JOYSTICKS)
66 nesPins [joysticks].dPin = dPin ;
67 nesPins [joysticks].cPin = cPin ;
68 nesPins [joysticks].lPin = lPin ;
70 digitalWrite (lPin, LOW) ;
71 digitalWrite (cPin, LOW) ;
73 pinMode (lPin, OUTPUT) ;
74 pinMode (cPin, OUTPUT) ;
75 pinMode (dPin, INPUT) ;
83 * Do a single scan of the NES Joystick.
84 *********************************************************************************
87 unsigned int readNesJoystick (int joystick)
89 unsigned int value = 0 ;
92 struct nesPinsStruct *pins = &nesPins [joystick] ;
94 // Toggle Latch - which presents the first bit
96 digitalWrite (pins->lPin, HIGH) ; delayMicroseconds (PULSE_TIME) ;
97 digitalWrite (pins->lPin, LOW) ; delayMicroseconds (PULSE_TIME) ;
101 value = digitalRead (pins->dPin) ;
103 // Now get the next 7 bits with the clock
105 for (i = 0 ; i < 7 ; ++i)
107 digitalWrite (pins->cPin, HIGH) ; delayMicroseconds (PULSE_TIME) ;
108 digitalWrite (pins->cPin, LOW) ; delayMicroseconds (PULSE_TIME) ;
109 value = (value << 1) | digitalRead (pins->dPin) ;
112 return value ^ 0xFF ;