* lfuse: BODLEVEL=1 BODEN=1 SUT1=1 SUT0=1 CKSEL3=1 CKSEL2=1 CKSEL1=1 CKSEL0=1
*/
+//#define NO_MODULATION
+#define WAIT_LASER
+//#define MODUL_455KHZ
+//#define MODUL_56KHZ
+#define MODUL_38KHZ
+//#define SPEED_40RPS
+#define SPEED_10RPS
+
+/* beacon identifier: must be odd, 3 bits */
+#define BEACON_ID 0x1
+#define BEACON_ID_MASK 0x7
+#define BEACON_ID_SHIFT 0
+
+/* */
+#define FRAME_DATA_MASK 0xFFF8
+#define FRAME_DATA_SHIFT 3
+
+#if (defined MODUL_455KHZ)
#define N_PERIODS 10
#define N_CYCLES_0 17
#define N_CYCLES_1 17
+#elif (defined MODUL_56KHZ)
+#define N_PERIODS 15
+#define N_CYCLES_0 143
+#define N_CYCLES_1 143
+#elif (defined MODUL_38KHZ)
+#define N_PERIODS 15
+#define N_CYCLES_0 210
+#define N_CYCLES_1 210
+#else
+#error "no freq defined"
+#endif
+
#define N_CYCLES_PERIOD (N_CYCLES_0 + N_CYCLES_1)
#define LED_PORT PORTD
#define LED3_BIT 7
#define LED_TOGGLE(port, bit) do { \
- if (port & _BV(bit)) \
- port &= ~_BV(bit); \
- else \
- port |= _BV(bit); \
- } while(0)
+ if (port & _BV(bit)) \
+ port &= ~_BV(bit); \
+ else \
+ port |= _BV(bit); \
+ } while(0)
#define LED1_ON() sbi(LED_PORT, LED1_BIT)
#define LED1_OFF() cbi(LED_PORT, LED1_BIT)
#define FRAME_LEN 16
/* pin returns !0 when nothing, and 0 when laser is on photodiode */
-#define PHOTO_PIN PINC
+#define PHOTO_PIN PINB
#define PHOTO_BIT 0
#define READ_PHOTO() (!!(PHOTO_PIN & (_BV(PHOTO_BIT))))
-#define MIN_INTER_TIME (50*16) /* t~=50us dist=350cm */
-#define MAX_INTER_TIME (2000*16) /* t=2ms 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
+/* IR_DELAY **must** be < 32768 */
+#if (defined SPEED_10RPS)
+#define MIN_INTER_TIME ((uint16_t)(160*2)) /* t~=160us dist=350cm */
+#define MAX_INTER_TIME ((uint16_t)(8000*2)) /* t=8ms dist=10cm */
+#define IR_DELAY ((uint16_t)(8000*2))
+#define INTER_LASER_TIME 30 /* in ms */
+#elif (defined SPEED_40RPS)
+#define MIN_INTER_TIME ((uint16_t)(40*16)) /* t~=40us dist=350cm */
+#define MAX_INTER_TIME ((uint16_t)(2000*16)) /* t=2ms dist=10cm */
+#define IR_DELAY ((uint16_t)(2000*16))
+#define INTER_LASER_TIME 10 /* in ms */
+#else
+#error "speed not defined"
+#endif
/* basic functions to transmit on IR */
static inline void xmit_0(void)
{
- uint8_t t = ((N_CYCLES_PERIOD * N_PERIODS) / 3);
+ uint16_t t = ((N_CYCLES_PERIOD * N_PERIODS) / 4);
#ifdef NO_MODULATION
cbi(IR_PORT, IR_BIT);
#else
TCCR1B = 0;
TCCR1A = 0;
#endif
- _delay_loop_1(t); /* 3 cycles per loop */
+ _delay_loop_2(t); /* 4 cycles per loop */
}
static inline void xmit_1(void)
{
- uint8_t t = ((N_CYCLES_PERIOD * N_PERIODS) / 3);
+ uint16_t t = ((N_CYCLES_PERIOD * N_PERIODS) / 4);
#ifdef NO_MODULATION
sbi(IR_PORT, IR_BIT);
#else
TCCR1B = _BV(WGM13) | _BV(WGM12);
TCNT1 = N_CYCLES_PERIOD-1;
TCCR1A = _BV(COM1A1) | _BV(WGM11);
+ ICR1 = N_CYCLES_PERIOD;
TCCR1B = _BV(WGM13) | _BV(WGM12) | _BV(CS10);
#endif
- _delay_loop_1(t); /* 3 cycles per loop */
+ _delay_loop_2(t); /* 4 cycles per loop */
}
/* transmit in manchester code */
xmit_0();
}
+#ifdef WAIT_LASER
+/* get the frame from laser time difference */
+static uint32_t get_frame(uint16_t laserdiff)
+{
+ uint32_t frame = 0;
+ frame |= ((uint32_t)BEACON_ID << BEACON_ID_SHIFT);
+ frame |= ((uint32_t)(laserdiff & FRAME_DATA_MASK) << FRAME_DATA_SHIFT);
+ return frame;
+}
+
/* 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)
+ * IR signal should be sent. The 'laserdiff' pointer is the time
+ * between the 2 lasers, in timer unit. */
+static inline int8_t wait_laser(uint16_t *when, uint16_t *laserdiff)
{
uint16_t time1, time2;
uint16_t diff;
+#ifdef SPEED_40RPS
/* set timer to 16Mhz, we will use ICP */
TCCR1A = 0;
TCCR1B = _BV(CS10);
+#else /* 10 RPS */
+ /* set timer to 2Mhz, we will use ICP */
+ TCCR1A = 0;
+ TCCR1B = _BV(CS11);
+#endif
- /* wait until all is off */
- while (READ_PHOTO() != 0);
+ /* wait until all is off (inverted logic) */
+ while (READ_PHOTO() == 0);
TIFR = _BV(ICF1);
- /* wait rising edge */
+ /* wait falling edge */
while ((TIFR & _BV(ICF1)) == 0);
time1 = ICR1;
+
+ LED1_ON();
+
+ /* wait a bit to avoid oscillations */
+ while ((uint16_t)(TCNT1-time1) < MIN_INTER_TIME);
TIFR = _BV(ICF1);
- /* wait next rising edge + timeout */
+ /* wait next falling edge + timeout */
while ((TIFR & _BV(ICF1)) == 0) {
diff = TCNT1 - time1;
if (diff > MAX_INTER_TIME)
return -1;
}
+ LED2_ON();
+
+ /* get time of 2nd laser */
time2 = ICR1;
TIFR = _BV(ICF1);
+ /* process time difference */
diff = time2 - time1;
if (diff < MIN_INTER_TIME)
return -1;
*when = time1 + (diff/2) + IR_DELAY;
+ *laserdiff = diff;
/* laser ok */
return 0;
}
+#endif
/* */
{
/* must be odd */
uint32_t frame = FRAME;
+#ifdef WAIT_LASER
int8_t ret;
uint16_t when = 0;
-
+ uint16_t diff = 0;
+#endif
/* LEDS */
LED_DDR = _BV(LED1_BIT) | _BV(LED2_BIT) | _BV(LED3_BIT);
IR_DDR |= _BV(IR_BIT);
TCCR1B = _BV(WGM13) | _BV(WGM12);
#endif
+#if 0
+ /* test freq */
+ ICR1 = N_CYCLES_PERIOD;
+ OCR1A = N_CYCLES_1;
+ TCCR1B = _BV(WGM13) | _BV(WGM12);
+ TCNT1 = N_CYCLES_PERIOD-1;
+ TCCR1A = _BV(COM1A1) | _BV(WGM11);
+ TCCR1B = _BV(WGM13) | _BV(WGM12) | _BV(CS10);
+ while (1);
+#endif
+
+
/* configure timer 0, prescaler = 64 */
TCCR0 = _BV(CS01) | _BV(CS00);
while (1) {
#ifdef WAIT_LASER
- ret = wait_laser(&when);
+ ret = wait_laser(&when, &diff);
LED1_OFF();
LED2_OFF();
if (ret)
continue;
+ frame = get_frame(diff);
+
/* wait before IR xmit */
while ((int16_t)(when-TCNT1) > 0);
#endif
-#if 1
LED3_ON();
/* ok, transmit frame */
xmit_bits(frame, FRAME_LEN);
+ LED3_OFF();
+
/* don't watch a laser during this time */
wait_ms(INTER_LASER_TIME);
- LED3_OFF();
-#else
- LED1_ON();
- wait_ms(1);
- LED1_OFF();
-#endif
}
return 0;
}
git.droids-corp.org / aversive.git / commitdiff