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
42 #define N_CYCLES_PERIOD (N_CYCLES_0 + N_CYCLES_1)
44 #define LED_PORT PORTD
50 #define LED_TOGGLE(port, bit) do { \
51 if (port & _BV(bit)) \
57 #define LED1_ON() sbi(LED_PORT, LED1_BIT)
58 #define LED1_OFF() cbi(LED_PORT, LED1_BIT)
59 #define LED1_TOGGLE() LED_TOGGLE(LED_PORT, LED1_BIT)
60 #define LED2_ON() sbi(LED_PORT, LED2_BIT)
61 #define LED2_OFF() cbi(LED_PORT, LED2_BIT)
62 #define LED2_TOGGLE() LED_TOGGLE(LED_PORT, LED2_BIT)
63 #define LED3_ON() sbi(LED_PORT, LED3_BIT)
64 #define LED3_OFF() cbi(LED_PORT, LED3_BIT)
65 #define LED3_TOGGLE() LED_TOGGLE(LED_PORT, LED3_BIT)
71 /* FRAME must be odd */
72 /* #define FRAME 0x0B /\* in little endian 1-1-0-1 *\/ */
73 /* #define FRAME_LEN 4 */
74 #define FRAME 0xAA5B /* in little endian */
77 /* pin returns !0 when nothing, and 0 when laser is on photodiode */
78 #define PHOTO_PIN PINC
80 #define READ_PHOTO() (!!(PHOTO_PIN & (_BV(PHOTO_BIT))))
82 #define MIN_INTER_TIME (50*16) /* t~=50us dist=350cm */
83 #define MAX_INTER_TIME (2000*16) /* t=2ms dist=20cm */
85 /* xmit 2ms after virtual laser: must be < 32768 */
86 #define IR_DELAY (2000*16)
89 #define INTER_LASER_TIME 10
91 //#define NO_MODULATION
94 /* basic functions to transmit on IR */
96 static inline void xmit_0(void)
98 uint8_t t = ((N_CYCLES_PERIOD * N_PERIODS) / 3);
100 cbi(IR_PORT, IR_BIT);
105 _delay_loop_1(t); /* 3 cycles per loop */
108 static inline void xmit_1(void)
110 uint8_t t = ((N_CYCLES_PERIOD * N_PERIODS) / 3);
112 sbi(IR_PORT, IR_BIT);
114 TCCR1B = _BV(WGM13) | _BV(WGM12);
115 TCNT1 = N_CYCLES_PERIOD-1;
116 TCCR1A = _BV(COM1A1) | _BV(WGM11);
117 TCCR1B = _BV(WGM13) | _BV(WGM12) | _BV(CS10);
119 _delay_loop_1(t); /* 3 cycles per loop */
122 /* transmit in manchester code */
124 static inline void xmit_manchester_0(void)
130 static inline void xmit_manchester_1(void)
136 /* transmit a full frame. Each byte is lsb first. */
138 static void xmit_bits(uint32_t frame, uint8_t nbit)
142 for (i=0; i<nbit; i++) {
154 /* Wait 2 consecutive rising edges on photodiode. Return 0 on success,
155 * in this case, the 'when' pointed area is assigned to the time when
156 * IR signal should be sent. */
157 static inline int8_t wait_laser(uint16_t *when)
159 uint16_t time1, time2;
162 /* set timer to 16Mhz, we will use ICP */
166 /* wait until all is off */
167 while (READ_PHOTO() != 0);
170 /* wait rising edge */
171 while ((TIFR & _BV(ICF1)) == 0);
175 /* wait next rising edge + timeout */
176 while ((TIFR & _BV(ICF1)) == 0) {
177 diff = TCNT1 - time1;
178 if (diff > MAX_INTER_TIME)
185 diff = time2 - time1;
186 if (diff < MIN_INTER_TIME)
189 *when = time1 + (diff/2) + IR_DELAY;
200 uint32_t frame = FRAME;
205 LED_DDR = _BV(LED1_BIT) | _BV(LED2_BIT) | _BV(LED3_BIT);
206 IR_DDR |= _BV(IR_BIT);
209 fdevopen(uart0_dev_send, uart0_dev_recv);
215 c = uart_recv_nowait(0);
217 printf("%c", (char)(c+1));
234 #ifndef NO_MODULATION
236 ICR1 = N_CYCLES_PERIOD;
238 TCCR1A = _BV(COM1A1) | _BV(WGM11);
239 TCCR1B = _BV(WGM13) | _BV(WGM12);
242 /* configure timer 0, prescaler = 64 */
243 TCCR0 = _BV(CS01) | _BV(CS00);
248 ret = wait_laser(&when);
256 /* wait before IR xmit */
257 while ((int16_t)(when-TCNT1) > 0);
262 /* ok, transmit frame */
263 xmit_bits(frame, FRAME_LEN);
265 /* don't watch a laser during this time */
266 wait_ms(INTER_LASER_TIME);