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annotate 1wire.c @ 11:ccc39c9f320b
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| author | darius |
|---|---|
| date | Fri, 16 Jul 2004 23:39:58 +0930 |
| parents | eb1faf51968e |
| children | 4b141cc7cbd4 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 * Various 1 wire routines | |
| 3 * Search routine is copied from the Dallas owpd library with mods. | |
| 4 * | |
|
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5 * $Id$ |
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6 * |
| 0 | 7 * Copyright (c) 2004 |
| 8 * Daniel O'Connor <darius@dons.net.au>. All rights reserved. | |
| 9 * | |
| 10 * Redistribution and use in source and binary forms, with or without | |
| 11 * modification, are permitted provided that the following conditions | |
| 12 * are met: | |
| 13 * 1. Redistributions of source code must retain the above copyright | |
| 14 * notice, this list of conditions and the following disclaimer. | |
| 15 * 2. Redistributions in binary form must reproduce the above copyright | |
| 16 * notice, this list of conditions and the following disclaimer in the | |
| 17 * documentation and/or other materials provided with the distribution. | |
| 18 * | |
| 19 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND | |
| 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 22 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE | |
| 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
| 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
| 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
| 29 * SUCH DAMAGE. | |
| 30 */ | |
| 31 | |
| 32 #include <stdio.h> | |
| 33 #include <avr/io.h> | |
| 34 #include <avr/pgmspace.h> | |
| 35 | |
| 36 #include "1wire.h" | |
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37 #include "1wire-delay.h" |
| 0 | 38 |
| 39 void uart_putsP(const char *addr); | |
| 40 void uart_puts(const char *addr); | |
| 41 void uart_getc(); | |
| 42 int uart_putc(char c); | |
| 43 | |
| 44 static uint8_t OW_LastDevice = 0; | |
| 45 static uint8_t OW_LastDiscrepancy = 0; | |
| 46 static uint8_t OW_LastFamilyDiscrepancy = 0; | |
| 47 | |
| 48 static void | |
| 49 OWdelay(void) { | |
| 10 | 50 DELAY_I; |
| 0 | 51 } |
| 52 | |
| 53 /*----------------------------------------------------------------------------- | |
| 54 * Generate a 1-Wire reset, return 1 if no presence detect was found, | |
| 55 * return 0 otherwise. | |
| 56 * (NOTE: Does not handle alarm presence from DS2404/DS1994) | |
| 57 */ | |
| 58 int | |
| 59 OWTouchReset(void) { | |
| 10 | 60 DELAY_G; |
| 61 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); | |
| 62 OWIREDDR |= _BV(OWIREOUTPIN); | |
| 63 DELAY_H; | |
| 64 OWIREDDR &= ~(_BV(OWIREOUTPIN)); | |
| 65 DELAY_I; | |
| 0 | 66 |
| 10 | 67 return(OWIREINPORT & _BV(OWIREINPIN) ? 1 : 0); |
| 0 | 68 } |
| 69 | |
| 70 /*----------------------------------------------------------------------------- | |
| 71 * Send a 1-wire write bit. | |
| 72 */ | |
| 73 void | |
| 74 OWWriteBit(int bit) { | |
| 75 OWdelay(); | |
| 76 if (bit) { | |
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77 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); |
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78 OWIREDDR |= _BV(OWIREOUTPIN); |
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79 DELAY_A; |
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80 OWIREDDR &= ~(_BV(OWIREOUTPIN)); |
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81 DELAY_B; |
| 0 | 82 } else { |
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83 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); |
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84 OWIREDDR |= _BV(OWIREOUTPIN); |
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85 DELAY_C; |
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86 OWIREDDR &= ~(_BV(OWIREOUTPIN)); |
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87 DELAY_D; |
| 0 | 88 } |
| 89 } | |
| 90 | |
| 91 /*----------------------------------------------------------------------------- | |
| 92 * Read a bit from the 1-wire bus and return it. | |
| 93 */ | |
| 94 int | |
| 95 OWReadBit(void) { | |
| 96 OWdelay(); | |
| 97 | |
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98 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); |
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99 OWIREDDR |= _BV(OWIREOUTPIN); |
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100 DELAY_A; |
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101 OWIREDDR &= ~(_BV(OWIREOUTPIN)); |
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102 DELAY_E; |
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103 return(OWIREINPORT & _BV(OWIREINPIN) ? 1 : 0); |
| 0 | 104 } |
| 105 | |
| 106 /*----------------------------------------------------------------------------- | |
| 107 * Write a byte to the 1-wire bus | |
| 108 */ | |
| 109 void | |
| 110 OWWriteByte(uint8_t data) { | |
| 111 int i; | |
| 112 | |
| 113 /* Send LSB first */ | |
| 114 for (i = 0; i < 8; i++) { | |
| 115 OWWriteBit(data & 0x01); | |
| 116 data >>= 1; | |
| 117 } | |
| 118 } | |
| 119 | |
| 120 /*----------------------------------------------------------------------------- | |
| 121 * Read a byte from the 1-wire bus | |
| 122 */ | |
| 123 int | |
| 124 OWReadByte(void) { | |
| 125 int i, result = 0; | |
| 126 | |
| 127 for (i = 0; i < 8; i++) { | |
| 128 result >>= 1; | |
| 129 if (OWReadBit()) | |
| 130 result |= 0x80; | |
| 131 } | |
| 132 return(result); | |
| 133 } | |
| 134 | |
| 135 /*----------------------------------------------------------------------------- | |
| 136 * Write a 1-wire data byte and return the sampled result. | |
| 137 */ | |
| 138 int | |
| 139 OWTouchByte(uint8_t data) { | |
| 140 int i, result = 0; | |
| 141 | |
| 142 for (i = 0; i < 8; i++) { | |
| 143 result >>= 1; | |
| 144 | |
| 145 /* If sending a 1 then read a bit, otherwise write a 0 */ | |
| 146 if (data & 0x01) { | |
| 147 if (OWReadBit()) | |
| 148 result |= 0x80; | |
| 149 } else | |
| 150 OWWriteBit(0); | |
| 151 | |
| 152 data >>= 1; | |
| 153 } | |
| 154 | |
| 155 return(result); | |
| 156 } | |
| 157 | |
| 158 /*----------------------------------------------------------------------------- | |
| 159 * Write a block of bytes to the 1-wire bus and return the sampled result in | |
| 160 * the same buffer | |
| 161 */ | |
| 162 void | |
| 163 OWBlock(uint8_t *data, int len) { | |
| 164 int i; | |
| 165 | |
| 166 for (i = 0; i < len; i++) | |
| 167 data[i] = OWTouchByte(data[i]); | |
| 168 } | |
| 169 | |
| 170 | |
| 171 /*----------------------------------------------------------------------------- | |
| 172 * Send a 1 wire command to a device, or all if no ROM ID provided | |
| 173 */ | |
| 174 void | |
| 175 OWSendCmd(uint8_t *ROM, uint8_t cmd) { | |
| 176 int i; | |
| 177 | |
| 178 OWTouchReset(); | |
| 179 | |
| 180 if (ROM == NULL) | |
| 181 OWWriteByte(OW_SKIP_ROM_CMD); | |
| 182 else { | |
| 183 OWWriteByte(OW_MATCH_ROM_CMD); | |
| 184 for (i = 0; i < 8; i++) | |
| 185 OWWriteByte(ROM[i]); | |
| 186 } | |
| 187 | |
| 188 OWWriteByte(cmd); | |
| 189 } | |
| 190 | |
| 191 /*----------------------------------------------------------------------------- | |
| 192 * Search algorithm from App note 187 (and 162) | |
| 193 * | |
| 10 | 194 * OWFirst/OWNext return.. |
| 195 * 1 when something is found, | |
| 196 * 0 no more modules | |
| 197 * -1 if no presense pulse, | |
| 198 * -2 if bad CRC, | |
| 199 * -3 if bad wiring. | |
| 0 | 200 */ |
| 201 int | |
| 202 OWFirst(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) { | |
| 203 /* Reset state */ | |
| 204 OW_LastDiscrepancy = 0; | |
| 205 OW_LastDevice = 0; | |
| 206 OW_LastFamilyDiscrepancy = 0; | |
| 207 | |
| 208 /* Go looking */ | |
| 209 return (OWNext(ROM, do_reset, alarm_only)); | |
| 210 } | |
| 211 | |
| 212 /* Returns 1 when something is found, 0 if nothing left */ | |
| 213 int | |
| 214 OWNext(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) { | |
| 215 uint8_t bit_test, search_direction, bit_number; | |
| 10 | 216 uint8_t last_zero, rom_byte_number, rom_byte_mask; |
| 0 | 217 uint8_t lastcrc8, crcaccum; |
| 10 | 218 int next_result; |
| 0 | 219 char errstr[30]; |
| 220 | |
| 221 /* Init for search */ | |
| 222 bit_number = 1; | |
| 223 last_zero = 0; | |
| 224 rom_byte_number = 0; | |
| 225 rom_byte_mask = 1; | |
| 10 | 226 next_result = OW_NOMODULES; |
| 0 | 227 lastcrc8 = 0; |
| 228 crcaccum = 0; | |
| 229 | |
| 230 /* if the last call was not the last one */ | |
| 231 if (!OW_LastDevice) { | |
| 232 /* check if reset first is requested */ | |
| 233 if (do_reset) { | |
| 234 /* reset the 1-wire | |
| 235 * if there are no parts on 1-wire, return 0 */ | |
| 236 #if OW_DEBUG | |
| 237 uart_putsP(PSTR("Resetting\n\r")); | |
| 238 #endif | |
| 239 if (OWTouchReset()) { | |
| 240 /* reset the search */ | |
| 241 OW_LastDiscrepancy = 0; | |
| 242 OW_LastFamilyDiscrepancy = 0; | |
| 243 #if OW_DEBUG | |
| 244 uart_putsP(PSTR("No devices on bus\n\r")); | |
| 245 #endif | |
| 10 | 246 return OW_NOPRESENCE; |
| 0 | 247 } |
| 248 } | |
| 249 | |
| 250 /* If finding alarming devices issue a different command */ | |
| 251 if (alarm_only) | |
| 252 OWWriteByte(OW_SEARCH_ALRM_CMD); /* issue the alarming search command */ | |
| 253 else | |
| 254 OWWriteByte(OW_SEARCH_ROM_CMD); /* issue the search command */ | |
| 255 | |
| 256 /* pause before beginning the search */ | |
| 257 OWdelay(); | |
| 258 OWdelay(); | |
| 259 OWdelay(); | |
| 260 | |
| 261 /* loop to do the search */ | |
| 262 do { | |
| 263 /* read a bit and its compliment */ | |
| 264 bit_test = OWReadBit() << 1; | |
| 265 bit_test |= OWReadBit(); | |
| 266 | |
| 267 #if OW_DEBUG | |
| 268 sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test); | |
| 269 uart_puts(errstr); | |
| 270 #endif | |
| 271 | |
| 272 /* check for no devices on 1-wire */ | |
| 273 if (bit_test == 3) { | |
| 10 | 274 #if OW_DEBUG |
| 0 | 275 sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test); |
| 276 uart_puts(errstr); | |
| 10 | 277 #endif |
| 278 return(OW_BADWIRE); | |
| 0 | 279 } |
| 280 else { | |
| 281 /* all devices coupled have 0 or 1 */ | |
| 282 if (bit_test > 0) | |
| 283 search_direction = !(bit_test & 0x01); /* bit write value for search */ | |
| 284 else { | |
| 285 /* if this discrepancy is before the Last Discrepancy | |
| 286 * on a previous OWNext then pick the same as last time */ | |
| 287 if (bit_number < OW_LastDiscrepancy) | |
| 288 search_direction = ((ROM[rom_byte_number] & rom_byte_mask) > 0); | |
| 289 else | |
| 290 /* if equal to last pick 1, if not then pick 0 */ | |
| 291 search_direction = (bit_number == OW_LastDiscrepancy); | |
| 292 | |
| 293 /* if 0 was picked then record its position in LastZero */ | |
| 294 if (search_direction == 0) { | |
| 295 last_zero = bit_number; | |
| 296 | |
| 297 /* check for Last discrepancy in family */ | |
| 298 if (last_zero < 9) | |
| 299 OW_LastFamilyDiscrepancy = last_zero; | |
| 300 } | |
| 301 } | |
| 302 | |
| 303 /* set or clear the bit in the ROM byte rom_byte_number | |
| 304 * with mask rom_byte_mask */ | |
| 305 if (search_direction == 1) | |
| 306 ROM[rom_byte_number] |= rom_byte_mask; | |
| 307 else | |
| 308 ROM[rom_byte_number] &= ~rom_byte_mask; | |
| 309 | |
| 310 /* serial number search direction write bit */ | |
| 311 OWWriteBit(search_direction); | |
| 312 | |
| 313 /* increment the byte counter bit_number | |
| 314 * and shift the mask rom_byte_mask */ | |
| 315 bit_number++; | |
| 316 rom_byte_mask <<= 1; | |
| 317 | |
| 318 /* if the mask is 0 then go to new ROM byte rom_byte_number | |
| 319 * and reset mask */ | |
| 320 if (rom_byte_mask == 0) { | |
| 321 OWCRC(ROM[rom_byte_number], &crcaccum); /* accumulate the CRC */ | |
| 322 lastcrc8 = crcaccum; | |
| 323 | |
| 324 rom_byte_number++; | |
| 325 rom_byte_mask = 1; | |
| 326 } | |
| 327 } | |
| 328 } while (rom_byte_number < 8); /* loop until through all ROM bytes 0-7 */ | |
| 329 | |
| 330 /* if the search was successful then */ | |
| 331 if (!(bit_number < 65) || lastcrc8) { | |
| 332 if (lastcrc8) { | |
| 333 sprintf_P(errstr, PSTR("Bad CRC (%d)\n\r"), lastcrc8); | |
| 334 uart_puts(errstr); | |
| 10 | 335 next_result = OW_BADCRC; |
| 0 | 336 } else { |
| 337 /* search successful so set LastDiscrepancy,LastDevice,next_result */ | |
| 338 OW_LastDiscrepancy = last_zero; | |
| 339 OW_LastDevice = (OW_LastDiscrepancy == 0); | |
| 340 #if OW_DEBUG | |
| 341 sprintf_P(errstr, PSTR("Last device = %d\n\r"), OW_LastDevice); | |
| 342 uart_puts(errstr); | |
| 343 #endif | |
| 10 | 344 next_result = OW_FOUND; |
| 0 | 345 } |
| 346 } | |
| 347 } | |
| 348 | |
| 349 /* if no device found then reset counters so next 'next' will be | |
| 350 * like a first */ | |
| 10 | 351 if (next_result != OW_FOUND || ROM[0] == 0) { |
| 0 | 352 OW_LastDiscrepancy = 0; |
| 353 OW_LastDevice = 0; | |
| 354 OW_LastFamilyDiscrepancy = 0; | |
| 355 } | |
| 356 | |
| 10 | 357 if (next_result == OW_FOUND && ROM[0] == 0x00) |
| 358 next_result = OW_BADWIRE; | |
| 359 | |
| 0 | 360 return next_result; |
| 361 | |
| 362 } | |
| 363 | |
| 364 uint8_t PROGMEM dscrc_table[] = { | |
| 365 0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65, | |
| 366 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220, | |
| 367 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98, | |
| 368 190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255, | |
| 369 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7, | |
| 370 219, 133,103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154, | |
| 371 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36, | |
| 372 248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185, | |
| 373 140,210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113,147, 205, | |
| 374 17, 79, 173, 243, 112, 46, 204, 146, 211,141, 111, 49, 178, 236, 14, 80, | |
| 375 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82,176, 238, | |
| 376 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115, | |
| 377 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139, | |
| 378 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22, | |
| 379 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168, | |
| 380 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53 | |
| 381 }; | |
| 382 | |
| 383 void | |
| 384 OWCRC(uint8_t x, uint8_t *crc) { | |
| 385 *crc = pgm_read_byte(&dscrc_table[(*crc) ^ x]); | |
| 386 } |