initial cleanup and mapping

wiringPi/softTone.c

@@ -0,0 +1,150 @@
+/*
+ * softTone.c:
+ *	For that authentic retro sound...
+ *	Er... A little experiment to produce tones out of a Pi using
+ *	one (or 2) GPIO pins and a piezeo "speaker" element.
+ *	(Or a high impedance speaker, but don'y blame me if you blow-up
+ *	the GPIO pins!)
+ *	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 <stdio.h>
+#include <pthread.h>
+
+#include "wiringPi.h"
+#include "softTone.h"
+
+#define	MAX_PINS	64
+
+#define	PULSE_TIME	100
+
+static int freqs         [MAX_PINS] ;
+static pthread_t threads [MAX_PINS] ;
+
+static int newPin = -1 ;
+
+
+/*
+ * softToneThread:
+ *	Thread to do the actual PWM output
+ *********************************************************************************
+ */
+
+static PI_THREAD (softToneThread)
+{
+  int pin, freq, halfPeriod ;
+  struct sched_param param ;
+
+  param.sched_priority = sched_get_priority_max (SCHED_RR) ;
+  pthread_setschedparam (pthread_self (), SCHED_RR, &param) ;
+
+  pin    = newPin ;
+  newPin = -1 ;
+
+  piHiPri (50) ;
+
+  for (;;)
+  {
+    freq = freqs [pin] ;
+    if (freq == 0)
+      delay (1) ;
+    else
+    {
+      halfPeriod = 500000 / freq ;
+
+      digitalWrite (pin, HIGH) ;
+      delayMicroseconds (halfPeriod) ;
+
+      digitalWrite (pin, LOW) ;
+      delayMicroseconds (halfPeriod) ;
+    }
+  }
+
+  return NULL ;
+}
+
+
+/*
+ * softToneWrite:
+ *	Write a frequency value to the given pin
+ *********************************************************************************
+ */
+
+void softToneWrite (int pin, int freq)
+{
+  pin &= 63 ;
+
+  /**/ if (freq < 0)
+    freq = 0 ;
+  else if (freq > 5000)	// Max 5KHz
+    freq = 5000 ;
+
+  freqs [pin] = freq ;
+}
+
+
+/*
+ * softToneCreate:
+ *	Create a new tone thread.
+ *********************************************************************************
+ */
+
+int softToneCreate (int pin)
+{
+  int res ;
+  pthread_t myThread ;
+
+  pinMode      (pin, OUTPUT) ;
+  digitalWrite (pin, LOW) ;
+
+  if (threads [pin] != 0)
+    return -1 ;
+
+  freqs [pin] = 0 ;
+
+  newPin = pin ;
+  res    = pthread_create (&myThread, NULL, softToneThread, NULL) ;
+
+  while (newPin != -1)
+    delay (1) ;
+
+  threads [pin] = myThread ;
+
+  return res ;
+}
+
+
+/*
+ * softToneStop:
+ *	Stop an existing softTone thread
+ *********************************************************************************
+ */
+
+void softToneStop (int pin)
+{
+  if (threads [pin] != 0)
+  {
+    pthread_cancel (threads [pin]) ;
+    pthread_join   (threads [pin], NULL) ;
+    threads [pin] = 0 ;
+    digitalWrite (pin, LOW) ;
+  }
+}