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annotate 1wire.c @ 21:e82d15fa9a1a
Re-format the code.
| author | darius |
|---|---|
| date | Mon, 12 Dec 2005 23:01:00 +1030 |
| parents | 026dc24d85e0 |
| children | bd792ebf813d |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 * Various 1 wire routines | |
| 12 | 3 * Search routine is copied from the Dallas owpd library with mods |
| 4 * available from here http://www.ibutton.com/software/1wire/wirekit.html | |
| 0 | 5 * |
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6 * $Id$ |
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7 * |
| 0 | 8 * Copyright (c) 2004 |
| 9 * Daniel O'Connor <darius@dons.net.au>. All rights reserved. | |
| 10 * | |
| 11 * Redistribution and use in source and binary forms, with or without | |
| 12 * modification, are permitted provided that the following conditions | |
| 13 * are met: | |
| 14 * 1. Redistributions of source code must retain the above copyright | |
| 15 * notice, this list of conditions and the following disclaimer. | |
| 16 * 2. Redistributions in binary form must reproduce the above copyright | |
| 17 * notice, this list of conditions and the following disclaimer in the | |
| 18 * documentation and/or other materials provided with the distribution. | |
| 19 * | |
| 20 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND | |
| 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 23 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE | |
| 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
| 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
| 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
| 30 * SUCH DAMAGE. | |
| 31 */ | |
| 32 | |
| 33 #include <stdio.h> | |
| 34 #include <avr/io.h> | |
| 35 #include <avr/pgmspace.h> | |
| 21 | 36 #include <util/delay.h> |
| 0 | 37 #include "1wire.h" |
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38 #include "1wire-delay.h" |
| 0 | 39 |
| 12 | 40 #if OW_DEBUG |
| 0 | 41 void uart_putsP(const char *addr); |
| 42 void uart_puts(const char *addr); | |
| 43 void uart_getc(); | |
| 21 | 44 char uart_putc(char c); |
| 12 | 45 #endif |
| 0 | 46 |
| 47 static uint8_t OW_LastDevice = 0; | |
| 48 static uint8_t OW_LastDiscrepancy = 0; | |
| 49 static uint8_t OW_LastFamilyDiscrepancy = 0; | |
| 50 | |
| 51 static void | |
| 52 OWdelay(void) { | |
| 10 | 53 DELAY_I; |
| 0 | 54 } |
| 55 | |
| 56 /*----------------------------------------------------------------------------- | |
| 12 | 57 * Generate a 1-Wire reset, return 0 if presence pulse was found, |
| 58 * return 1 otherwise. | |
| 21 | 59 * |
| 0 | 60 * (NOTE: Does not handle alarm presence from DS2404/DS1994) |
| 61 */ | |
| 12 | 62 uint8_t |
| 0 | 63 OWTouchReset(void) { |
| 10 | 64 DELAY_G; |
| 65 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); | |
| 66 OWIREDDR |= _BV(OWIREOUTPIN); | |
| 67 DELAY_H; | |
| 68 OWIREDDR &= ~(_BV(OWIREOUTPIN)); | |
| 69 DELAY_I; | |
| 0 | 70 |
| 10 | 71 return(OWIREINPORT & _BV(OWIREINPIN) ? 1 : 0); |
| 0 | 72 } |
| 73 | |
| 74 /*----------------------------------------------------------------------------- | |
| 75 * Send a 1-wire write bit. | |
| 76 */ | |
| 77 void | |
| 12 | 78 OWWriteBit(uint8_t bit) { |
| 0 | 79 OWdelay(); |
| 80 if (bit) { | |
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81 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); |
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82 OWIREDDR |= _BV(OWIREOUTPIN); |
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83 DELAY_A; |
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84 OWIREDDR &= ~(_BV(OWIREOUTPIN)); |
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85 DELAY_B; |
| 0 | 86 } else { |
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87 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); |
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88 OWIREDDR |= _BV(OWIREOUTPIN); |
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89 DELAY_C; |
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90 OWIREDDR &= ~(_BV(OWIREOUTPIN)); |
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91 DELAY_D; |
| 0 | 92 } |
| 93 } | |
| 94 | |
| 95 /*----------------------------------------------------------------------------- | |
| 96 * Read a bit from the 1-wire bus and return it. | |
| 97 */ | |
| 12 | 98 uint8_t |
| 0 | 99 OWReadBit(void) { |
| 100 OWdelay(); | |
| 101 | |
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102 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); |
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103 OWIREDDR |= _BV(OWIREOUTPIN); |
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104 DELAY_A; |
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105 OWIREDDR &= ~(_BV(OWIREOUTPIN)); |
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106 DELAY_E; |
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107 return(OWIREINPORT & _BV(OWIREINPIN) ? 1 : 0); |
| 0 | 108 } |
| 109 | |
| 110 /*----------------------------------------------------------------------------- | |
| 111 * Write a byte to the 1-wire bus | |
| 112 */ | |
| 113 void | |
| 114 OWWriteByte(uint8_t data) { | |
| 12 | 115 uint8_t i; |
| 0 | 116 |
| 117 /* Send LSB first */ | |
| 118 for (i = 0; i < 8; i++) { | |
| 119 OWWriteBit(data & 0x01); | |
| 120 data >>= 1; | |
| 121 } | |
| 122 } | |
| 123 | |
| 124 /*----------------------------------------------------------------------------- | |
| 125 * Read a byte from the 1-wire bus | |
| 126 */ | |
| 12 | 127 uint8_t |
| 0 | 128 OWReadByte(void) { |
| 129 int i, result = 0; | |
| 130 | |
| 131 for (i = 0; i < 8; i++) { | |
| 132 result >>= 1; | |
| 133 if (OWReadBit()) | |
| 134 result |= 0x80; | |
| 135 } | |
| 136 return(result); | |
| 137 } | |
| 138 | |
| 139 /*----------------------------------------------------------------------------- | |
| 140 * Write a 1-wire data byte and return the sampled result. | |
| 141 */ | |
| 12 | 142 uint8_t |
| 0 | 143 OWTouchByte(uint8_t data) { |
| 12 | 144 uint8_t i, result = 0; |
| 0 | 145 |
| 146 for (i = 0; i < 8; i++) { | |
| 147 result >>= 1; | |
| 148 | |
| 149 /* If sending a 1 then read a bit, otherwise write a 0 */ | |
| 150 if (data & 0x01) { | |
| 151 if (OWReadBit()) | |
| 152 result |= 0x80; | |
| 153 } else | |
| 154 OWWriteBit(0); | |
| 155 | |
| 156 data >>= 1; | |
| 157 } | |
| 158 | |
| 159 return(result); | |
| 160 } | |
| 161 | |
| 162 /*----------------------------------------------------------------------------- | |
| 163 * Write a block of bytes to the 1-wire bus and return the sampled result in | |
| 164 * the same buffer | |
| 165 */ | |
| 166 void | |
| 167 OWBlock(uint8_t *data, int len) { | |
| 168 int i; | |
| 169 | |
| 170 for (i = 0; i < len; i++) | |
| 171 data[i] = OWTouchByte(data[i]); | |
| 172 } | |
| 173 | |
| 174 | |
| 175 /*----------------------------------------------------------------------------- | |
| 176 * Send a 1 wire command to a device, or all if no ROM ID provided | |
| 177 */ | |
| 178 void | |
| 179 OWSendCmd(uint8_t *ROM, uint8_t cmd) { | |
| 12 | 180 uint8_t i; |
| 0 | 181 |
| 182 OWTouchReset(); | |
| 183 | |
| 184 if (ROM == NULL) | |
| 185 OWWriteByte(OW_SKIP_ROM_CMD); | |
| 186 else { | |
| 187 OWWriteByte(OW_MATCH_ROM_CMD); | |
| 188 for (i = 0; i < 8; i++) | |
| 189 OWWriteByte(ROM[i]); | |
| 190 } | |
| 191 | |
| 192 OWWriteByte(cmd); | |
| 193 } | |
| 194 | |
| 195 /*----------------------------------------------------------------------------- | |
| 196 * Search algorithm from App note 187 (and 162) | |
| 197 * | |
| 10 | 198 * OWFirst/OWNext return.. |
| 199 * 1 when something is found, | |
| 200 * 0 no more modules | |
| 16 | 201 * -1 if no presence pulse, |
| 10 | 202 * -2 if bad CRC, |
| 203 * -3 if bad wiring. | |
| 0 | 204 */ |
| 12 | 205 uint8_t |
| 0 | 206 OWFirst(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) { |
| 207 /* Reset state */ | |
| 208 OW_LastDiscrepancy = 0; | |
| 209 OW_LastDevice = 0; | |
| 210 OW_LastFamilyDiscrepancy = 0; | |
| 211 | |
| 212 /* Go looking */ | |
| 213 return (OWNext(ROM, do_reset, alarm_only)); | |
| 214 } | |
| 215 | |
| 216 /* Returns 1 when something is found, 0 if nothing left */ | |
| 12 | 217 uint8_t |
| 0 | 218 OWNext(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) { |
| 219 uint8_t bit_test, search_direction, bit_number; | |
| 10 | 220 uint8_t last_zero, rom_byte_number, rom_byte_mask; |
| 0 | 221 uint8_t lastcrc8, crcaccum; |
| 12 | 222 int8_t next_result; |
| 0 | 223 |
| 224 /* Init for search */ | |
| 21 | 225 bit_number = 1; |
| 226 last_zero = 0; | |
| 227 rom_byte_number = 0; | |
| 228 rom_byte_mask = 1; | |
| 229 next_result = OW_NOMODULES; | |
| 230 lastcrc8 = 0; | |
| 231 crcaccum = 0; | |
| 0 | 232 |
| 21 | 233 /* if the last call was not the last one */ |
| 234 if (!OW_LastDevice) { | |
| 235 /* check if reset first is requested */ | |
| 236 if (do_reset) { | |
| 237 /* reset the 1-wire | |
| 238 * if there are no parts on 1-wire, return 0 */ | |
| 0 | 239 #if OW_DEBUG |
| 21 | 240 uart_putsP(PSTR("Resetting\n\r")); |
| 0 | 241 #endif |
| 21 | 242 if (OWTouchReset()) { |
| 243 /* reset the search */ | |
| 244 OW_LastDiscrepancy = 0; | |
| 245 OW_LastFamilyDiscrepancy = 0; | |
| 0 | 246 #if OW_DEBUG |
| 21 | 247 uart_putsP(PSTR("No devices on bus\n\r")); |
| 0 | 248 #endif |
| 21 | 249 return OW_NOPRESENCE; |
| 250 } | |
| 251 } | |
| 0 | 252 |
| 21 | 253 /* If finding alarming devices issue a different command */ |
| 254 if (alarm_only) | |
| 255 OWWriteByte(OW_SEARCH_ALRM_CMD); /* issue the alarming search command */ | |
| 256 else | |
| 257 OWWriteByte(OW_SEARCH_ROM_CMD); /* issue the search command */ | |
| 0 | 258 |
| 21 | 259 /* pause before beginning the search */ |
| 260 OWdelay(); | |
| 261 OWdelay(); | |
| 262 OWdelay(); | |
| 0 | 263 |
| 21 | 264 /* loop to do the search */ |
| 265 do { | |
| 266 /* read a bit and its compliment */ | |
| 267 bit_test = OWReadBit() << 1; | |
| 268 bit_test |= OWReadBit(); | |
| 0 | 269 |
| 270 #if OW_DEBUG | |
| 21 | 271 sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test); |
| 272 uart_puts(errstr); | |
| 0 | 273 #endif |
| 274 | |
| 21 | 275 /* check for no devices on 1-wire */ |
| 276 if (bit_test == 3) { | |
| 10 | 277 #if OW_DEBUG |
| 21 | 278 sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test); |
| 279 uart_puts(errstr); | |
| 10 | 280 #endif |
| 21 | 281 return(OW_BADWIRE); |
| 282 } | |
| 283 else { | |
| 284 /* all devices coupled have 0 or 1 */ | |
| 285 if (bit_test > 0) | |
| 286 search_direction = !(bit_test & 0x01); /* bit write value for search */ | |
| 287 else { | |
| 288 /* if this discrepancy is before the Last Discrepancy | |
| 289 * on a previous OWNext then pick the same as last time */ | |
| 290 if (bit_number < OW_LastDiscrepancy) | |
| 291 search_direction = ((ROM[rom_byte_number] & rom_byte_mask) > 0); | |
| 292 else | |
| 293 /* if equal to last pick 1, if not then pick 0 */ | |
| 294 search_direction = (bit_number == OW_LastDiscrepancy); | |
| 0 | 295 |
| 21 | 296 /* if 0 was picked then record its position in LastZero */ |
| 297 if (search_direction == 0) { | |
| 298 last_zero = bit_number; | |
| 0 | 299 |
| 21 | 300 /* check for Last discrepancy in family */ |
| 301 if (last_zero < 9) | |
| 302 OW_LastFamilyDiscrepancy = last_zero; | |
| 303 } | |
| 304 } | |
| 0 | 305 |
| 21 | 306 /* set or clear the bit in the ROM byte rom_byte_number |
| 307 * with mask rom_byte_mask */ | |
| 308 if (search_direction == 1) | |
| 309 ROM[rom_byte_number] |= rom_byte_mask; | |
| 310 else | |
| 311 ROM[rom_byte_number] &= ~rom_byte_mask; | |
| 0 | 312 |
| 21 | 313 /* serial number search direction write bit */ |
| 314 OWWriteBit(search_direction); | |
| 0 | 315 |
| 21 | 316 /* increment the byte counter bit_number |
| 317 * and shift the mask rom_byte_mask */ | |
| 318 bit_number++; | |
| 319 rom_byte_mask <<= 1; | |
| 0 | 320 |
| 21 | 321 /* if the mask is 0 then go to new ROM byte rom_byte_number |
| 322 * and reset mask */ | |
| 323 if (rom_byte_mask == 0) { | |
| 324 OWCRC(ROM[rom_byte_number], &crcaccum); /* accumulate the CRC */ | |
| 325 lastcrc8 = crcaccum; | |
| 0 | 326 |
| 21 | 327 rom_byte_number++; |
| 328 rom_byte_mask = 1; | |
| 329 } | |
| 330 } | |
| 331 } while (rom_byte_number < 8); /* loop until through all ROM bytes 0-7 */ | |
| 0 | 332 |
| 21 | 333 /* if the search was successful then */ |
| 334 if (!(bit_number < 65) || lastcrc8) { | |
| 335 if (lastcrc8) { | |
| 12 | 336 #if OW_DEBUG |
| 21 | 337 sprintf_P(errstr, PSTR("Bad CRC (%d)\n\r"), lastcrc8); |
| 338 uart_puts(errstr); | |
| 12 | 339 #endif |
| 21 | 340 next_result = OW_BADCRC; |
| 341 } else { | |
| 342 /* search successful so set LastDiscrepancy,LastDevice,next_result */ | |
| 343 OW_LastDiscrepancy = last_zero; | |
| 344 OW_LastDevice = (OW_LastDiscrepancy == 0); | |
| 0 | 345 #if OW_DEBUG |
| 21 | 346 sprintf_P(errstr, PSTR("Last device = %d\n\r"), OW_LastDevice); |
| 347 uart_puts(errstr); | |
| 0 | 348 #endif |
| 21 | 349 next_result = OW_FOUND; |
| 350 } | |
| 351 } | |
| 352 } | |
| 0 | 353 |
| 21 | 354 /* if no device found then reset counters so next 'next' will be |
| 355 * like a first */ | |
| 356 if (next_result != OW_FOUND || ROM[0] == 0) { | |
| 357 OW_LastDiscrepancy = 0; | |
| 358 OW_LastDevice = 0; | |
| 359 OW_LastFamilyDiscrepancy = 0; | |
| 360 } | |
| 0 | 361 |
| 21 | 362 if (next_result == OW_FOUND && ROM[0] == 0x00) |
| 363 next_result = OW_BADWIRE; | |
| 10 | 364 |
| 21 | 365 return next_result; |
| 0 | 366 |
| 367 } | |
| 368 | |
| 369 uint8_t PROGMEM dscrc_table[] = { | |
| 370 0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65, | |
| 371 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220, | |
| 372 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98, | |
| 373 190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255, | |
| 374 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7, | |
| 375 219, 133,103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154, | |
| 376 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36, | |
| 377 248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185, | |
| 378 140,210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113,147, 205, | |
| 379 17, 79, 173, 243, 112, 46, 204, 146, 211,141, 111, 49, 178, 236, 14, 80, | |
| 380 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82,176, 238, | |
| 381 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115, | |
| 382 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139, | |
| 383 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22, | |
| 384 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168, | |
| 385 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53 | |
| 386 }; | |
| 387 | |
| 388 void | |
| 389 OWCRC(uint8_t x, uint8_t *crc) { | |
| 390 *crc = pgm_read_byte(&dscrc_table[(*crc) ^ x]); | |
| 391 } |