From 67d9ed5abb311bc08673af15111dd6c38a9cf5b1 Mon Sep 17 00:00:00 2001 From: Olivier Matz Date: Sat, 6 Mar 2010 22:53:55 +0100 Subject: [PATCH 1/1] static_beacon --- .../tests/static_beacon/static_beacon.c | 145 +++++++++++++----- 1 file changed, 109 insertions(+), 36 deletions(-) diff --git a/projects/microb2010/tests/static_beacon/static_beacon.c b/projects/microb2010/tests/static_beacon/static_beacon.c index c8e54c0..08b4251 100755 --- a/projects/microb2010/tests/static_beacon/static_beacon.c +++ b/projects/microb2010/tests/static_beacon/static_beacon.c @@ -36,9 +36,39 @@ * 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 @@ -48,11 +78,11 @@ #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) @@ -75,48 +105,52 @@ #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 */ @@ -151,46 +185,74 @@ static void xmit_bits(uint32_t frame, uint8_t nbit) 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 /* */ @@ -198,9 +260,11 @@ int main(void) { /* 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); @@ -239,13 +303,25 @@ int main(void) 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(); @@ -253,23 +329,20 @@ int main(void) 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; } -- 2.20.1