static beacon

[aversive.git] / projects / microb2010 / tests / static_beacon / static_beacon.c

diff --git a/projects/microb2010/tests/static_beacon/static_beacon.c b/projects/microb2010/tests/static_beacon/static_beacon.c
index c34838c..c8e54c0 100755 (executable)
--- a/projects/microb2010/tests/static_beacon/static_beacon.c
+++ b/projects/microb2010/tests/static_beacon/static_beacon.c
@@ -79,12 +79,11 @@
 #define PHOTO_BIT 0
 #define READ_PHOTO() (!!(PHOTO_PIN & (_BV(PHOTO_BIT))))
 
-/* in cycles/64 (unit is 4 us at 16Mhz) */
-#define MAX_PHOTO_TIME ((uint8_t)25)  /* t=100us len=5mm rps=40Hz dist=20cm */
+#define MIN_INTER_TIME (50*16)  /* t~=50us dist=350cm */
+#define MAX_INTER_TIME (2000*16) /* t=2ms dist=20cm */
 
-/* XXX to be recalculated */
-#define MIN_INTER_TIME ((uint8_t)12)  /* t=50us len=50mm rps=40Hz dist=350cm */
-#define MAX_INTER_TIME ((uint8_t)250) /* t=1000us len=50mm rps=40Hz dist=20cm */
+/* xmit 2ms after virtual laser: must be < 32768 */
+#define IR_DELAY (2000*16)
 
 /* in ms */
 #define INTER_LASER_TIME 10
@@ -152,59 +151,43 @@ static void xmit_bits(uint32_t frame, uint8_t nbit)
        xmit_0();
 }
 
-/* */
-static inline int8_t wait_laser(void)
+/* Wait 2 consecutive rising edges on photodiode. Return 0 on success,
+ * in this case, the 'when' pointed area is assigned to the time when
+ * IR signal should be sent. */
+static inline int8_t wait_laser(uint16_t *when)
 {
-       uint8_t photos;
-       uint8_t time1, time2;
-       uint8_t diff;
-
-       /*
-         wait photo on
-         wait photo off
-         wait photo on or timeout
-         wait photo off
-         should return the amount of time to wait
-        */
+       uint16_t time1, time2;
+       uint16_t diff;
+
+       /* set timer to 16Mhz, we will use ICP */
+       TCCR1A = 0;
+       TCCR1B = _BV(CS10);
 
        /* wait until all is off */
        while (READ_PHOTO() != 0);
+       TIFR = _BV(ICF1);
 
-       /* wait until photo is on */
-       while (READ_PHOTO() != 1);
-       time1 = TCNT0;
-       LED1_ON();
-
-       /* wait until photo is off, if it takes too long time,
-        * return. */
-       while (READ_PHOTO() != 0) {
-               diff = TCNT0 - time1;
-               if (diff > MAX_PHOTO_TIME)
-                       return -1;
-       }
+       /* wait rising edge */
+       while ((TIFR & _BV(ICF1)) == 0);
+       time1 = ICR1;
+       TIFR = _BV(ICF1);
 
-       /* wait photo on. */
-       while (READ_PHOTO() != 1) {
-               diff = TCNT0 - time1;
+       /* wait next rising edge + timeout */
+       while ((TIFR & _BV(ICF1)) == 0) {
+               diff = TCNT1 - time1;
                if (diff > MAX_INTER_TIME)
                        return -1;
        }
-       time2 = TCNT0;
 
-       /* wait until photo is off, if it takes too long time,
-        * return. */
-       while (READ_PHOTO() != 0) {
-               diff = TCNT0 - time2;
-               if (diff > MAX_PHOTO_TIME)
-                       return -1;
-       }
-
-       LED2_ON();
+       time2 = ICR1;
+       TIFR = _BV(ICF1);
 
        diff = time2 - time1;
        if (diff < MIN_INTER_TIME)
                return -1;
 
+       *when = time1 + (diff/2) + IR_DELAY;
+
        /* laser ok */
        return 0;
 }
@@ -216,7 +199,7 @@ int main(void)
        /* must be odd */
        uint32_t frame = FRAME;
        int8_t ret;
-       int16_t c;
+       uint16_t when = 0;
 
        /* LEDS */
        LED_DDR = _BV(LED1_BIT) | _BV(LED2_BIT) | _BV(LED3_BIT);
@@ -228,6 +211,7 @@ int main(void)
 
 #if 0
        while (1) {
+               int16_t c;
                c = uart_recv_nowait(0);
                if (c != -1)
                        printf("%c", (char)(c+1));
@@ -240,7 +224,7 @@ int main(void)
 
 #if 0
        while (1) {
-               if (READ_PHOTO() & _BV(PHOTO1_BIT))
+               if (READ_PHOTO())
                        LED1_ON();
                else
                        LED1_OFF();
@@ -261,13 +245,16 @@ int main(void)
        while (1) {
 
 #ifdef WAIT_LASER
-               ret = wait_laser();
+               ret = wait_laser(&when);
 
                LED1_OFF();
                LED2_OFF();
 
                if (ret)
                        continue;
+
+               /* wait before IR xmit */
+               while ((int16_t)(when-TCNT1) > 0);
 #endif
 
 #if 1