changed to hardware interrupt for ppm input

controller.ino

@@ -7,12 +7,14 @@
 //to flash set boot0 (the one further away from reset button) to 1 and press reset, flash, program executes immediately
 //set boot0 back to 0 to run program on powerup
 
+//#define DEBUG
+
 #define PIN_LED PC13
 
 #define PIN_POTI1 PA7
 #define PIN_POTI2 PA6
 
-#define SENDPERIOD 50
+#define SENDPERIOD 20
 
 
 uint16_t poti1=0;
@@ -24,17 +26,43 @@ long last_send=0;
 int16_t out_steer=0;
 int16_t out_speed=0;
 
+
+volatile long t_raising1=0;
+volatile long t_falling1=0;
+volatile long t_raising2=0;
+volatile long t_falling2=0;
+volatile long t_raising3=0;
+volatile long t_falling3=0;
+volatile long t_raising4=0;
+volatile long t_falling4=0;
+
+long last_updated_ch1=0;
+long last_updated_ch2=0;
+long last_updated_ch3=0;
+long last_updated_ch4=0;
+
+
+long ppmlagmillis=0; //updated by ppmOK()
+boolean flag_ppmupdated=false; //true if at least one ppm value (chx_in) updated
+
+
+#define MAXPPMUPDATETIME 50 //max time it should take to update a ppm channel value (otherwise ppmOK() will return false)
 uint16_t ch1_in;
 uint16_t ch2_in;
 uint16_t ch3_in;
 uint16_t ch4_in;
+//ch1 = steer (ail)
+  //ch2 = speed (ele)
+  //ch3 = speed multiplier (thr)
 
-//RC Input Pins
 #define PIN_CH1 PB9
 #define PIN_CH2 PB8
 #define PIN_CH3 PB7
 #define PIN_CH4 PB6
 
+#define PPM_TIME_MIN 900
+#define PPM_TIME_MAX 2100
+
 
 void setup() {
 
@@ -51,22 +79,20 @@ void setup() {
 
 
   pinMode(PIN_CH1, INPUT);
+  attachInterrupt(PIN_CH1, ppmchanged1, CHANGE); //see http://docs.leaflabs.com/static.leaflabs.com/pub/leaflabs/maple-docs/0.0.12/lang/api/attachinterrupt.html
   pinMode(PIN_CH2, INPUT);
+  attachInterrupt(PIN_CH2, ppmchanged2, CHANGE);
   pinMode(PIN_CH3, INPUT);
+  attachInterrupt(PIN_CH3, ppmchanged3, CHANGE);
   pinMode(PIN_CH4, INPUT);
+  attachInterrupt(PIN_CH4, ppmchanged4, CHANGE);
 
 }
 
 void loop() {
 
-  //RC Input.  chn_in between 0 and 1000
+  updateChannels(); //calculate chx_in times from ppm signals. 0 <= chx_in <= 1000
-  ch1_in = constrain(map(pulseIn(PIN_CH1, HIGH, 25000),1000,2000, 0,1000), 0,1000); //Read Pulse Width. (pulseIn values typically between 1000 and 2000). Map and constrain between 0 and 1000
+  boolean _ppmOK=ppmOK();
-  ch2_in = constrain(map(pulseIn(PIN_CH2, HIGH, 25000),1000,2000, 0,1000), 0,1000);
-  //ch3_in = constrain(map(pulseIn(PIN_CH3, HIGH, 25000),1000,2000, 0,1000), 0,1000);
-  //ch4_in = constrain(map(pulseIn(PIN_CH4, HIGH, 25000),1000,2000, 0,1000), 0,1000);
-  //ch1 = steer (ail)
-  //ch2 = speed (ele)
-  //ch3 = speed multiplier (thr)
 
   //Potis
   /*poti1=analogRead(PIN_POTI1);
@@ -91,20 +117,148 @@ void loop() {
   out_steer=0;
   */
 
-  //out_speed=(int16_t)( (ch2_in*2-1000)*(ch3_in/1000.0) );
+
-  out_speed=(int16_t)( (ch2_in*2-1000));
+  if (_ppmOK){ //ppm check failed   
-  out_steer=ch1_in*2-1000;
+    //out_speed=(int16_t)( (ch2_in*2-1000)*(ch3_in/1000.0) );
+    out_speed=(int16_t)( (ch2_in*2-1000));
+    out_steer=ch1_in*2-1000;
+  }else{
+    //out_speed=(int16_t)( (ch2_in*2-1000)*(ch3_in/1000.0) );
+    out_speed=0; //stop
+    out_steer=0; //stop
+  }
+
+  
+
+  if (flag_ppmupdated){
+    flag_ppmupdated=false; //clear flag
+    digitalWrite(PIN_LED,!digitalRead(PIN_LED)); //toggle led
+  }
+
 
   if (millis()-last_send>SENDPERIOD){
     Serial2.write((uint8_t *) &out_steer, sizeof(out_steer)); 
     Serial2.write((uint8_t *) &out_speed, sizeof(out_speed));
     last_send=millis();
 
-    Serial.print("Steer=");
+
-    Serial.println(out_steer);
+    #ifdef DEBUG
-    Serial.print("Speed=");
+    Serial.print("steer=");
-    Serial.println(out_speed);
+    Serial.print(out_steer);
+    Serial.print(" speed=");
+    Serial.print(out_speed);
+    /*
+    Serial.print(ch1_in);
+    Serial.print(",");
+    Serial.print(ch2_in);
+    Serial.print(",");
+    Serial.print(ch3_in);
+    Serial.print(",");
+    Serial.print(ch4_in);
+    */
+    Serial.print(", ppmOK=");
+    Serial.print(_ppmOK);
+    Serial.print(", ppmlag=");
+    Serial.print(ppmlagmillis);
+    #endif
+
+    
     Serial.println();
   }
 
 }
+
+
+
+void updateChannels(){
+  long funcmillis=millis();
+  //Calculate Pulse Width. (pulseIn values typically between 1000 and 2000). Map and constrain between 0 and 1000
+  long new_ch1_in=(t_falling1-t_raising1);
+  if (new_ch1_in>=PPM_TIME_MIN && new_ch1_in<=PPM_TIME_MAX){ //time valid and has changed
+    ch1_in=constrain(map(new_ch1_in,1000,2000, 0,1000), 0,1000);
+    last_updated_ch1=funcmillis;
+    flag_ppmupdated=true;
+  }
+  
+  long new_ch2_in=(t_falling2-t_raising2);
+  if (new_ch2_in>=PPM_TIME_MIN && new_ch2_in<=PPM_TIME_MAX){ //time valid and has changed
+    ch2_in=constrain(map(new_ch2_in,1000,2000, 0,1000), 0,1000);
+    last_updated_ch2=funcmillis;
+    flag_ppmupdated=true;
+  }
+  
+  long new_ch3_in=(t_falling3-t_raising3);
+  if (new_ch3_in>=PPM_TIME_MIN && new_ch3_in<=PPM_TIME_MAX){ //time valid and has changed
+    ch3_in=constrain(map(new_ch3_in,1000,2000, 0,1000), 0,1000);
+    last_updated_ch3=funcmillis;
+    flag_ppmupdated=true;
+  }
+  
+  long new_ch4_in=(t_falling4-t_raising4);
+  if (new_ch4_in>=PPM_TIME_MIN && new_ch4_in<=PPM_TIME_MAX){ //time valid and has changed
+    ch4_in=constrain(map(new_ch4_in,1000,2000, 0,1000), 0,1000);
+    last_updated_ch4=funcmillis;
+    flag_ppmupdated=true;
+  }
+
+}
+
+boolean ppmOK(){
+  long m=millis();
+  boolean returnvalue=true;
+  ppmlagmillis=0;
+  long v;
+  v=m-last_updated_ch1;
+  if (v>ppmlagmillis){ ppmlagmillis=v; }
+  if (v>MAXPPMUPDATETIME){
+    returnvalue=false;
+  }
+  v=m-last_updated_ch2;
+  if (v>ppmlagmillis){ ppmlagmillis=v; }
+  if (v>MAXPPMUPDATETIME){
+    returnvalue=false;
+  }
+  v=m-last_updated_ch3;
+  if (v>ppmlagmillis){ ppmlagmillis=v; }
+  if (v>MAXPPMUPDATETIME){
+    returnvalue=false;
+  }
+  v=m-last_updated_ch4;
+  if (v>ppmlagmillis){ ppmlagmillis=v; }
+  if (v>MAXPPMUPDATETIME){
+    returnvalue=false;
+  }
+  return returnvalue;
+}
+
+void ppmchanged1(){
+  if (digitalRead(PIN_CH1)){
+    t_raising1=micros();
+  }else{
+    t_falling1=micros();
+  }
+}
+
+void ppmchanged2(){
+  if (digitalRead(PIN_CH2)){
+    t_raising2=micros();
+  }else{
+    t_falling2=micros();
+  }
+}
+
+void ppmchanged3(){
+  if (digitalRead(PIN_CH3)){
+    t_raising3=micros();
+  }else{
+    t_falling3=micros();
+  }
+}
+
+void ppmchanged4(){
+  if (digitalRead(PIN_CH4)){
+    t_raising4=micros();
+  }else{
+    t_falling4=micros();
+  }
+}