*
*/
+#include <math.h>
+
#include <aversive.h>
#include <aversive/wait.h>
* 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 0x0FF8
+#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 MIN_DIST 150.
+#define MAX_DIST 3600.
+#define LASER_DIST 25.
+
#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))))
-/* in cycles/64 (unit is 4 us at 16Mhz) */
-#define MAX_PHOTO_TIME ((uint8_t)25) /* t=100us len=5mm rps=40Hz 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 */
-
-/* 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();
}
-/* */
-static inline int8_t wait_laser(void)
+#ifdef WAIT_LASER
+/* val is 12 bits. Return the 16 bits value that includes the 4 bits
+ * cksum in MSB. */
+static uint16_t do_cksum(uint16_t val)
{
- 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
- */
-
- /* wait until all is off */
- while (READ_PHOTO() != 0);
-
- /* wait until photo is on */
- while (READ_PHOTO() != 1);
- time1 = TCNT0;
+ uint16_t x, cksum;
+
+ x = (val & 0xfff);
+ /* add the three 4-bits blocks of x together */
+ cksum = x & 0xf;
+ x = x >> 4;
+ cksum += x & 0xf;
+ cksum = (cksum & 0xf) + ((cksum & 0xf0) >> 4);
+ x = x >> 4;
+ cksum += x & 0xf;
+ cksum = (cksum & 0xf) + ((cksum & 0xf0) >> 4);
+ cksum = (~cksum) & 0xf;
+ return (cksum << 12) + (val & 0xfff);
+}
+
+/* get the frame from laser time difference, return 0 on error (this
+ * frame cannot be sent). */
+static uint32_t get_frame(uint16_t laserdiff)
+{
+ uint32_t frame = 0;
+ double a, d;
+ uint16_t frame_dist;
+
+ frame |= ((uint32_t)BEACON_ID << BEACON_ID_SHIFT);
+
+ /* process angle from laserdiff time */
+#ifdef SPEED_10RPS
+ /* timer = 2Mhz */
+ a = ((double)laserdiff / (2000000./10.)) * 2. * M_PI;
+#else
+ /* timer = 16Mhz */
+ a = ((double)laserdiff / (16000000./40.)) * 2. * M_PI;
+#endif
+ /* get distance from angle */
+ d = LASER_DIST / sin(a/2);
+
+ /* scale it between 0 and 511 */
+ if (d <= MIN_DIST)
+ return 0;
+ if (d >= MAX_DIST)
+ return 0;
+ d -= MIN_DIST;
+ d /= (MAX_DIST-MIN_DIST);
+ d *= 512;
+ frame_dist = (uint16_t)d;
+ if (frame_dist >= 512) /* should not happen... */
+ return 0;
+
+ frame |= ((uint32_t)(frame_dist & FRAME_DATA_MASK) << FRAME_DATA_SHIFT);
+
+ /* process cksum and return */
+ return do_cksum(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. 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 (inverted logic) */
+ while (READ_PHOTO() == 0);
+ TIFR = _BV(ICF1);
+
+ /* wait falling edge */
+ while ((TIFR & _BV(ICF1)) == 0);
+ time1 = ICR1;
+
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 a bit to avoid oscillations */
+ while ((uint16_t)(TCNT1-time1) < MIN_INTER_TIME);
+ TIFR = _BV(ICF1);
- /* wait photo on. */
- while (READ_PHOTO() != 1) {
- diff = TCNT0 - time1;
+ /* wait next falling 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();
+ /* 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;
- int16_t c;
-
+ 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);
#if 0
while (1) {
+ int16_t c;
c = uart_recv_nowait(0);
if (c != -1)
printf("%c", (char)(c+1));
#if 0
while (1) {
- if (READ_PHOTO() & _BV(PHOTO1_BIT))
+ if (READ_PHOTO())
LED1_ON();
else
LED1_OFF();
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();
+ ret = wait_laser(&when, &diff);
LED1_OFF();
LED2_OFF();
if (ret)
continue;
+
+ frame = get_frame(diff);
+ /* cannot convert into frame... skip it */
+ if (frame == 0) {
+ wait_ms(INTER_LASER_TIME);
+ continue;
+ }
+
+ /* 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 / blobdiff