initial cleanup and mapping

devLib/piNes.c

@@ -0,0 +1,113 @@
+/*
+ * 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 ;
+}