correct transmission timing and add inter-transmission pause

pic/ACT-34B/ACT-34B.c

@@ -40,8 +40,10 @@
 /* variables */
 // a megacode is 3 bytes long (MSB of byte 1 is 1)
 # define CODE 0xc917c2
-// transmitting (0: do not transmit, 1: transmit, -1: finish transmiting)
+// transmitting (0: do not transmit, 1: transmit, -1: finish transmiting, -2: pause before next transmission)
 volatile int8_t transmit = 0;
+// the number or timer 2 overflow (0x06554s) to wait before next transmission
+volatile int8_t pause = 0;
  // the 4 phases of the bit (2ms pause, 1ms pulse, 2ms pause, 1ms pulse. only transmit during one of the two pulse periode depending on the bit value)
 volatile uint8_t phase = 0;
 // save the GPIO state to be able to figure out which changed
@@ -57,20 +59,17 @@ uint16_t __at(_CONFIG) __CONFIG = _WRT_OFF & // entire memory write protected
                                   _WDTE_OFF & // disable watchdog
                                   _INTRC_OSC_NOCLKOUT; // use internal oscillator and both I/O pins
 
-/* set timer in ms */
-#define TICKS_PER_MS 125UL // the number of timer 1 ticks to wait for 1ms, using the internal 4MHz clock and a prescaler of 8, and hand tuning
-
 void timer_1ms() {
   TMR1ON = 0; // disable timer 1 (to write value safely)
-  TMR1L = (0xffff-1*TICKS_PER_MS); // set time
-  TMR1H = (0xffff-1*TICKS_PER_MS)>>8; // set time
+  TMR1L = 0x88; // set time (tuned per hand)
+  TMR1H = 0xff; // set time
   TMR1ON = 1; // start timer 1
 }
 
 void timer_2ms() {
   TMR1ON = 0; // disable timer 1 (to write value safely)
-  TMR1L = (0xffff-2*TICKS_PER_MS); // set time
-  TMR1H = (0xffff-2*TICKS_PER_MS)>>8; // set time
+  TMR1L = 0x23; // set time (tuned per hand)
+  TMR1H = 0xff; // set time
   TMR1ON = 1; // start timer 1
 }
 
@@ -94,11 +93,15 @@ void megacode (void) {
       timer_2ms();
     } else { // restart after 25th bit
       phase = 0xff; // phase will be 0 after incrementing
+      clock_off(); // stop clock
       if (transmit == -1) { // stop transmiting if requested
         transmit = 0; // stop transmiting
-        clock_off(); // stop clock
+      } else {  // pause before next transmission
+        transmit = -2; // pause state
+        TMR2 = 0; // clear timer 2 (used to measure timer)
+        pause = 0; // reset number of timer 2 overflows (65.54ms)
+        TMR2ON = 1; // start timer 2
       }
-      timer_1ms();
     }
     phase++; // go to next phase
   }
@@ -118,6 +121,7 @@ void init (void) {
   GPIE = 1; // enable interrupt on GPIO
   last_gpio = GPIO; // save current state
 
+  /* use precise timer 1 for the megacode transmission timing */
   T1CON = _T1CKPS1 | _T1CKPS0; // set prescaler to 8
   // 0 is set per default, but just be sure
   TMR1ON = 0; // stop timer 1
@@ -127,6 +131,19 @@ void init (void) {
   PIE1 = 1; // enable timer 1 interrupt
   PEIE = 1; // enable timer interrupt
 
+  /* use timer 2 to separate two transmissions in time */
+  TMR2ON = 0; // switch off timer 2
+  T2CKPS0 = 1; // set prescaler to 16
+  T2CKPS1 = 1; // set prescaler to 16
+  TOUTPS0 = 1; // set postscaler to 16
+  TOUTPS1 = 1; // set postscaler to 16
+  TOUTPS2 = 1; // set postscaler to 16
+  TOUTPS3 = 1; // set postscaler to 16
+  PR2 = 0xff; // set interrupt on overflow
+  TMR2 = 0; // clear timer counter
+  TMR2IE = 1; // enable timer 2 interrupt
+  TMR2IF = 0; // clear timer 2 interrupt
+
   GIE = 1; // enable interrups
 
 }
@@ -137,9 +154,9 @@ static void interrupt(void) __interrupt 0
 {
   if (GPIF) { // pin state changed
     last_gpio ^= GPIO; // figure out which GPIO changed
-    if (last_gpio&SWITCH2) { // switch 1 (bigger button on top right) changed
-      if (GPIO&SWITCH2) { // button released, stop transmission
-        if (transmit == 1) { // currently transmitting
+    if (last_gpio&SWITCH4) { // switch 1 (bigger button on top right) changed
+      if (GPIO&SWITCH4) { // button released, stop transmission
+        if (transmit != 0) { // currently transmitting
           transmit = -1; // stop transmitting after last transmition
         }
       } else { // switch is pressed, start transmission
@@ -154,11 +171,24 @@ static void interrupt(void) __interrupt 0
     last_gpio = GPIO; // save current state
     GPIF = 0; // clear interrupt
   }
-  if (TMR1IF) { // timer 1 overflow
+  if (TMR1IF) { // timer 1 overflow, used to time megacode pulses
     megacode(); // continue sending megacode
     TMR1IF = 0; // clean interrupt
   }
-
+  if (TMR2IF) { // timer 2 overflow, used to pause between two transmissions
+    pause++; // number of timer 2 overflows (65.54ms)
+    if (transmit == -1) { // stop transmission
+      TMR2ON = 0; // stop counting pauses
+      transmit = 0; // stop transmission
+    } else if (pause==4) { // time between transmissions passed
+      transmit = 1;
+      phase = 0; // start from beginning
+      clock_on(); // start clock and leave it on during the whole transmission
+      megacode(); // start sending megacode
+      TMR2ON = 0; // stop counting pauses
+    }
+    TMR2IF = 0; // clean interrupt
+  }
 }
 
 void main (void)