2 * Copyright Droids Corporation (2009)
3 * Olivier Matz <zer0@droids-corp.org>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 * Revision : $Id: main.c,v 1.8 2009-05-02 10:08:09 zer0 Exp $
24 #include <aversive/wait.h>
30 * Photodiodes: PC0 PC1
35 * hfuse: RSTDISBL=1 WTDON=1 SPIEN=0 CKOPT=0 EESAVE=1 BOOTSZ1=0 BOOTSZ0=0 BOOTRST=1
36 * lfuse: BODLEVEL=1 BODEN=1 SUT1=1 SUT0=1 CKSEL3=1 CKSEL2=1 CKSEL1=1 CKSEL0=1
39 //#define NO_MODULATION
41 //#define MODUL_455KHZ
47 /* beacon identifier: must be odd, 3 bits */
49 #define BEACON_ID_MASK 0x7
50 #define BEACON_ID_SHIFT 0
53 #define FRAME_DATA_MASK 0xFFF8
54 #define FRAME_DATA_SHIFT 3
56 #if (defined MODUL_455KHZ)
60 #elif (defined MODUL_56KHZ)
62 #define N_CYCLES_0 143
63 #define N_CYCLES_1 143
64 #elif (defined MODUL_38KHZ)
66 #define N_CYCLES_0 210
67 #define N_CYCLES_1 210
69 #error "no freq defined"
72 #define N_CYCLES_PERIOD (N_CYCLES_0 + N_CYCLES_1)
74 #define LED_PORT PORTD
80 #define LED_TOGGLE(port, bit) do { \
81 if (port & _BV(bit)) \
87 #define LED1_ON() sbi(LED_PORT, LED1_BIT)
88 #define LED1_OFF() cbi(LED_PORT, LED1_BIT)
89 #define LED1_TOGGLE() LED_TOGGLE(LED_PORT, LED1_BIT)
90 #define LED2_ON() sbi(LED_PORT, LED2_BIT)
91 #define LED2_OFF() cbi(LED_PORT, LED2_BIT)
92 #define LED2_TOGGLE() LED_TOGGLE(LED_PORT, LED2_BIT)
93 #define LED3_ON() sbi(LED_PORT, LED3_BIT)
94 #define LED3_OFF() cbi(LED_PORT, LED3_BIT)
95 #define LED3_TOGGLE() LED_TOGGLE(LED_PORT, LED3_BIT)
101 /* FRAME must be odd */
102 /* #define FRAME 0x0B /\* in little endian 1-1-0-1 *\/ */
103 /* #define FRAME_LEN 4 */
104 #define FRAME 0xAA5B /* in little endian */
107 /* pin returns !0 when nothing, and 0 when laser is on photodiode */
108 #define PHOTO_PIN PINB
110 #define READ_PHOTO() (!!(PHOTO_PIN & (_BV(PHOTO_BIT))))
112 /* IR_DELAY **must** be < 32768 */
113 #if (defined SPEED_10RPS)
114 #define MIN_INTER_TIME ((uint16_t)(160*2)) /* t~=160us dist=350cm */
115 #define MAX_INTER_TIME ((uint16_t)(8000*2)) /* t=8ms dist=10cm */
116 #define IR_DELAY ((uint16_t)(8000*2))
117 #define INTER_LASER_TIME 30 /* in ms */
118 #elif (defined SPEED_40RPS)
119 #define MIN_INTER_TIME ((uint16_t)(40*16)) /* t~=40us dist=350cm */
120 #define MAX_INTER_TIME ((uint16_t)(2000*16)) /* t=2ms dist=10cm */
121 #define IR_DELAY ((uint16_t)(2000*16))
122 #define INTER_LASER_TIME 10 /* in ms */
124 #error "speed not defined"
127 /* basic functions to transmit on IR */
129 static inline void xmit_0(void)
131 uint16_t t = ((N_CYCLES_PERIOD * N_PERIODS) / 4);
133 cbi(IR_PORT, IR_BIT);
138 _delay_loop_2(t); /* 4 cycles per loop */
141 static inline void xmit_1(void)
143 uint16_t t = ((N_CYCLES_PERIOD * N_PERIODS) / 4);
145 sbi(IR_PORT, IR_BIT);
147 TCCR1B = _BV(WGM13) | _BV(WGM12);
148 TCNT1 = N_CYCLES_PERIOD-1;
149 TCCR1A = _BV(COM1A1) | _BV(WGM11);
150 ICR1 = N_CYCLES_PERIOD;
151 TCCR1B = _BV(WGM13) | _BV(WGM12) | _BV(CS10);
153 _delay_loop_2(t); /* 4 cycles per loop */
156 /* transmit in manchester code */
158 static inline void xmit_manchester_0(void)
164 static inline void xmit_manchester_1(void)
170 /* transmit a full frame. Each byte is lsb first. */
172 static void xmit_bits(uint32_t frame, uint8_t nbit)
176 for (i=0; i<nbit; i++) {
189 /* get the frame from laser time difference */
190 static uint32_t get_frame(uint16_t laserdiff)
193 frame |= ((uint32_t)BEACON_ID << BEACON_ID_SHIFT);
194 frame |= ((uint32_t)(laserdiff & FRAME_DATA_MASK) << FRAME_DATA_SHIFT);
198 /* Wait 2 consecutive rising edges on photodiode. Return 0 on success,
199 * in this case, the 'when' pointed area is assigned to the time when
200 * IR signal should be sent. The 'laserdiff' pointer is the time
201 * between the 2 lasers, in timer unit. */
202 static inline int8_t wait_laser(uint16_t *when, uint16_t *laserdiff)
204 uint16_t time1, time2;
208 /* set timer to 16Mhz, we will use ICP */
212 /* set timer to 2Mhz, we will use ICP */
217 /* wait until all is off (inverted logic) */
218 while (READ_PHOTO() == 0);
221 /* wait falling edge */
222 while ((TIFR & _BV(ICF1)) == 0);
227 /* wait a bit to avoid oscillations */
228 while ((uint16_t)(TCNT1-time1) < MIN_INTER_TIME);
231 /* wait next falling edge + timeout */
232 while ((TIFR & _BV(ICF1)) == 0) {
233 diff = TCNT1 - time1;
234 if (diff > MAX_INTER_TIME)
240 /* get time of 2nd laser */
244 /* process time difference */
245 diff = time2 - time1;
246 if (diff < MIN_INTER_TIME)
249 *when = time1 + (diff/2) + IR_DELAY;
262 uint32_t frame = FRAME;
269 LED_DDR = _BV(LED1_BIT) | _BV(LED2_BIT) | _BV(LED3_BIT);
270 IR_DDR |= _BV(IR_BIT);
273 fdevopen(uart0_dev_send, uart0_dev_recv);
279 c = uart_recv_nowait(0);
281 printf("%c", (char)(c+1));
298 #ifndef NO_MODULATION
300 ICR1 = N_CYCLES_PERIOD;
302 TCCR1A = _BV(COM1A1) | _BV(WGM11);
303 TCCR1B = _BV(WGM13) | _BV(WGM12);
308 ICR1 = N_CYCLES_PERIOD;
310 TCCR1B = _BV(WGM13) | _BV(WGM12);
311 TCNT1 = N_CYCLES_PERIOD-1;
312 TCCR1A = _BV(COM1A1) | _BV(WGM11);
313 TCCR1B = _BV(WGM13) | _BV(WGM12) | _BV(CS10);
318 /* configure timer 0, prescaler = 64 */
319 TCCR0 = _BV(CS01) | _BV(CS00);
324 ret = wait_laser(&when, &diff);
332 frame = get_frame(diff);
334 /* wait before IR xmit */
335 while ((int16_t)(when-TCNT1) > 0);
339 /* ok, transmit frame */
340 xmit_bits(frame, FRAME_LEN);
344 /* don't watch a laser during this time */
345 wait_ms(INTER_LASER_TIME);