-/*
+/*
* Copyright Droids Corporation (2009)
* Olivier Matz <zer0@droids-corp.org>
- *
+ *
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
/*
* hfuse: RSTDISBL=1 WTDON=1 SPIEN=0 CKOPT=0 EESAVE=1 BOOTSZ1=0 BOOTSZ0=0 BOOTRST=1
- * lfuse: BODLEVEL=1 BODEN=1 SUT1=1 SUT0=1 CKSEL3=1 CKSEL2=1 CKSEL1=1 CKSEL0=1
+ * lfuse: BODLEVEL=1 BODEN=1 SUT1=1 SUT0=1 CKSEL3=1 CKSEL2=1 CKSEL1=1 CKSEL0=1
*/
#define N_PERIODS 10
#define FRAME 0xAA5B /* in little endian */
#define FRAME_LEN 16
-/* pin returns 1 when nothing, and 0 when laser is on photodiode */
+/* pin returns !0 when nothing, and 0 when laser is on photodiode */
#define PHOTO_PIN PINC
-#define PHOTO1_BIT 0
-#define PHOTO2_BIT 1
-#define READ_PHOTOS() (PHOTO_PIN & (_BV(PHOTO1_BIT) | _BV(PHOTO2_BIT)))
-#define READ_PHOTO1() (PHOTO_PIN & _BV(PHOTO1_BIT))
-#define READ_PHOTO2() (PHOTO_PIN & _BV(PHOTO2_BIT))
-
-#define PHOTOS_ALL_OFF (_BV(PHOTO1_BIT) | _BV(PHOTO2_BIT))
-#define PHOTOS_ALL_ON (0)
-#define PHOTOS_1ON_2OFF (_BV(PHOTO2_BIT))
-#define PHOTOS_1OFF_2ON (_BV(PHOTO1_BIT))
-
+#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 */
-#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
-#define NO_MODULATION
-//#define WAIT_LASER
+//#define NO_MODULATION
+#define WAIT_LASER
/* basic functions to transmit on IR */
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 time;
- uint8_t diff;
-
- /* wait until all is off */
- while (READ_PHOTOS() != PHOTOS_ALL_OFF);
+ uint16_t time1, time2;
+ uint16_t diff;
- /* wait an event, it must be photo1 on */
- while ((photos = READ_PHOTOS()) == PHOTOS_ALL_OFF);
+ /* set timer to 16Mhz, we will use ICP */
+ TCCR1A = 0;
+ TCCR1B = _BV(CS10);
- if (photos != PHOTOS_1ON_2OFF)
- return -1;
- time = TCNT0;
- LED1_ON();
+ /* wait until all is off */
+ while (READ_PHOTO() != 0);
+ TIFR = _BV(ICF1);
- /* wait an event, it must be photo1 off */
- while ((photos = READ_PHOTOS()) == PHOTOS_1ON_2OFF) {
- diff = TCNT0 - time;
- if (diff > MAX_PHOTO_TIME)
- return -1;
- }
- if (photos != PHOTOS_ALL_OFF)
- return -1;
- //time = TCNT0;
+ /* wait rising edge */
+ while ((TIFR & _BV(ICF1)) == 0);
+ time1 = ICR1;
+ TIFR = _BV(ICF1);
- /* wait an event, it must be photo2 on */
- while ((photos = READ_PHOTOS()) == PHOTOS_ALL_OFF) {
- diff = TCNT0 - time;
+ /* wait next rising edge + timeout */
+ while ((TIFR & _BV(ICF1)) == 0) {
+ diff = TCNT1 - time1;
if (diff > MAX_INTER_TIME)
return -1;
}
- LED2_ON();
-
- diff = TCNT0 - time;
- if (diff < MIN_INTER_TIME)
- return -1;
- if (photos != PHOTOS_1OFF_2ON)
- return -1;
-#if 0
- time = TCNT0;
+ time2 = ICR1;
+ TIFR = _BV(ICF1);
- /* wait an event, it must be photo2 off */
- while ((photos = READ_PHOTOS()) == PHOTOS_1OFF_2ON) {
- diff = TCNT0 - time;
- if (diff > MAX_PHOTO_TIME)
- return -1;
- }
- if (photos != PHOTOS_ALL_OFF)
+ diff = time2 - time1;
+ if (diff < MIN_INTER_TIME)
return -1;
-#endif
+
+ *when = time1 + (diff/2) + IR_DELAY;
/* laser ok */
return 0;
/* 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);
#if 0
while (1) {
+ int16_t c;
c = uart_recv_nowait(0);
- if (c != -1)
+ if (c != -1)
printf("%c", (char)(c+1));
LED1_ON();
wait_ms(500);
#if 0
while (1) {
- if (READ_PHOTO() & _BV(PHOTO1_BIT))
+ if (READ_PHOTO())
LED1_ON();
else
LED1_OFF();
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
LED3_ON();
/* ok, transmit frame */
xmit_bits(frame, FRAME_LEN);
-
+
/* don't watch a laser during this time */
wait_ms(INTER_LASER_TIME);
LED3_OFF();
git.droids-corp.org / aversive.git / blobdiff