Mercurial > ~darius > hgwebdir.cgi > tempctrl
annotate 1wire.c @ 8:f9a085a0ba93
Change the 1 wire routines to mostly C with assembly delay routines
for ease of portability.
| author | darius |
|---|---|
| date | Mon, 12 Jul 2004 17:50:42 +0930 |
| parents | ffeab3c04e83 |
| children | eb1faf51968e |
| 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) { | |
| 50 asm volatile ( | |
| 51 "ldi r21, 50\n\t" | |
| 52 "_OWdelay:\n\t" | |
| 53 "nop\n\t" | |
| 54 "nop\n\t" | |
| 55 "nop\n\t" | |
| 56 "nop\n\t" | |
| 57 "nop\n\t" | |
| 58 "nop\n\t" | |
| 59 "nop\n\t" | |
| 60 "nop\n\t" | |
| 61 "nop\n\t" | |
| 62 "nop\n\t" | |
| 63 "nop\n\t" | |
| 64 "nop\n\t" | |
| 65 "nop\n\t" | |
| 66 "dec r21\n\t" | |
| 67 "brne _OWdelay\n\t" | |
| 68 ::: "r21"); | |
| 69 } | |
| 70 | |
| 71 /*----------------------------------------------------------------------------- | |
| 72 * Generate a 1-Wire reset, return 1 if no presence detect was found, | |
| 73 * return 0 otherwise. | |
| 74 * (NOTE: Does not handle alarm presence from DS2404/DS1994) | |
| 75 */ | |
| 76 int | |
| 77 OWTouchReset(void) { | |
| 78 uint8_t result; | |
| 79 | |
| 80 asm volatile ( | |
| 81 /* Delay G (0 usec) */ | |
| 82 "\n\t" | |
| 83 /* Drive bus low */ | |
| 84 "cbi %[out], %[opin]\n\t" | |
| 85 "sbi %[ddr], %[opin]\n\t" | |
| 86 /* Delay H (480 usec) */ | |
| 87 "ldi r21, 120\n\t" | |
| 88 "loopH:\n\t" | |
| 89 "nop\n\t" | |
| 90 "nop\n\t" | |
| 91 "nop\n\t" | |
| 92 "nop\n\t" | |
| 93 "nop\n\t" | |
| 94 "nop\n\t" | |
| 95 "nop\n\t" | |
| 96 "nop\n\t" | |
| 97 "nop\n\t" | |
| 98 "nop\n\t" | |
| 99 "nop\n\t" | |
| 100 "nop\n\t" | |
| 101 "nop\n\t" | |
| 102 "dec r21\n\t" | |
| 103 "brne loopH\n\t" | |
| 104 /* Release bus */ | |
| 105 "cbi %[ddr], %[opin]\n\t" | |
| 106 /* Delay I (70 usec) */ | |
| 107 "ldi r21, 35\n\t" | |
| 108 "loopI:\n\t" | |
| 109 "nop\n\t" | |
| 110 "nop\n\t" | |
| 111 "nop\n\t" | |
| 112 "nop\n\t" | |
| 113 "nop\n\t" | |
| 114 "dec r21\n\t" | |
| 115 "brne loopI\n\t" | |
| 116 /* Sample for presense */ | |
| 117 "ldi %[result], 0\n\t" | |
| 118 "sbi %[ddr], 1\n\t" | |
| 119 "sbi %[out], 1\n\t" | |
| 120 /* 1 == no presence */ | |
| 121 "sbic %[in], %[ipin]\n\t" | |
| 122 "ldi %[result], 1\n\t" | |
| 123 "cbi %[out], 1\n\t" | |
| 124 | |
| 125 : [result] "=r" (result) /* Outputs */ | |
| 126 : [out] "I" (_SFR_IO_ADDR(OWIREOUTPORT)), /* Inputs */ | |
| 127 [ddr] "I" (_SFR_IO_ADDR(OWIREDDR)), | |
| 128 [opin] "I" (OWIREOUTPIN), | |
| 129 [in] "I" (_SFR_IO_ADDR(OWIREINPORT)), | |
| 130 [ipin] "I" (OWIREINPIN) | |
| 131 : "r21"); /* Clobbers */ | |
| 132 | |
| 133 return(result); | |
| 134 } | |
| 135 | |
| 136 /*----------------------------------------------------------------------------- | |
| 137 * Send a 1-wire write bit. | |
| 138 */ | |
| 139 void | |
| 140 OWWriteBit(int bit) { | |
| 141 OWdelay(); | |
| 142 if (bit) { | |
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143 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); |
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144 OWIREDDR |= _BV(OWIREOUTPIN); |
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145 DELAY_A; |
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146 OWIREDDR &= ~(_BV(OWIREOUTPIN)); |
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147 DELAY_B; |
| 0 | 148 } else { |
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149 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); |
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150 OWIREDDR |= _BV(OWIREOUTPIN); |
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151 DELAY_C; |
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152 OWIREDDR &= ~(_BV(OWIREOUTPIN)); |
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153 DELAY_D; |
| 0 | 154 } |
| 155 } | |
| 156 | |
| 157 /*----------------------------------------------------------------------------- | |
| 158 * Read a bit from the 1-wire bus and return it. | |
| 159 */ | |
| 160 int | |
| 161 OWReadBit(void) { | |
| 162 OWdelay(); | |
| 163 | |
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164 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN)); |
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165 OWIREDDR |= _BV(OWIREOUTPIN); |
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166 DELAY_A; |
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167 OWIREDDR &= ~(_BV(OWIREOUTPIN)); |
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168 DELAY_E; |
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169 return(OWIREINPORT & _BV(OWIREINPIN) ? 1 : 0); |
| 0 | 170 } |
| 171 | |
| 172 /*----------------------------------------------------------------------------- | |
| 173 * Write a byte to the 1-wire bus | |
| 174 */ | |
| 175 void | |
| 176 OWWriteByte(uint8_t data) { | |
| 177 int i; | |
| 178 | |
| 179 /* Send LSB first */ | |
| 180 for (i = 0; i < 8; i++) { | |
| 181 OWWriteBit(data & 0x01); | |
| 182 data >>= 1; | |
| 183 } | |
| 184 } | |
| 185 | |
| 186 /*----------------------------------------------------------------------------- | |
| 187 * Read a byte from the 1-wire bus | |
| 188 */ | |
| 189 int | |
| 190 OWReadByte(void) { | |
| 191 int i, result = 0; | |
| 192 | |
| 193 for (i = 0; i < 8; i++) { | |
| 194 result >>= 1; | |
| 195 if (OWReadBit()) | |
| 196 result |= 0x80; | |
| 197 } | |
| 198 return(result); | |
| 199 } | |
| 200 | |
| 201 /*----------------------------------------------------------------------------- | |
| 202 * Write a 1-wire data byte and return the sampled result. | |
| 203 */ | |
| 204 int | |
| 205 OWTouchByte(uint8_t data) { | |
| 206 int i, result = 0; | |
| 207 | |
| 208 for (i = 0; i < 8; i++) { | |
| 209 result >>= 1; | |
| 210 | |
| 211 /* If sending a 1 then read a bit, otherwise write a 0 */ | |
| 212 if (data & 0x01) { | |
| 213 if (OWReadBit()) | |
| 214 result |= 0x80; | |
| 215 } else | |
| 216 OWWriteBit(0); | |
| 217 | |
| 218 data >>= 1; | |
| 219 } | |
| 220 | |
| 221 return(result); | |
| 222 } | |
| 223 | |
| 224 /*----------------------------------------------------------------------------- | |
| 225 * Write a block of bytes to the 1-wire bus and return the sampled result in | |
| 226 * the same buffer | |
| 227 */ | |
| 228 void | |
| 229 OWBlock(uint8_t *data, int len) { | |
| 230 int i; | |
| 231 | |
| 232 for (i = 0; i < len; i++) | |
| 233 data[i] = OWTouchByte(data[i]); | |
| 234 } | |
| 235 | |
| 236 | |
| 237 /*----------------------------------------------------------------------------- | |
| 238 * Send a 1 wire command to a device, or all if no ROM ID provided | |
| 239 */ | |
| 240 void | |
| 241 OWSendCmd(uint8_t *ROM, uint8_t cmd) { | |
| 242 int i; | |
| 243 | |
| 244 OWTouchReset(); | |
| 245 | |
| 246 if (ROM == NULL) | |
| 247 OWWriteByte(OW_SKIP_ROM_CMD); | |
| 248 else { | |
| 249 OWWriteByte(OW_MATCH_ROM_CMD); | |
| 250 for (i = 0; i < 8; i++) | |
| 251 OWWriteByte(ROM[i]); | |
| 252 } | |
| 253 | |
| 254 OWWriteByte(cmd); | |
| 255 } | |
| 256 | |
| 257 /*----------------------------------------------------------------------------- | |
| 258 * Search algorithm from App note 187 (and 162) | |
| 259 * | |
| 260 * Returns 1 when something is found, 0 if nothing present | |
| 261 */ | |
| 262 int | |
| 263 OWFirst(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) { | |
| 264 /* Reset state */ | |
| 265 OW_LastDiscrepancy = 0; | |
| 266 OW_LastDevice = 0; | |
| 267 OW_LastFamilyDiscrepancy = 0; | |
| 268 | |
| 269 /* Go looking */ | |
| 270 return (OWNext(ROM, do_reset, alarm_only)); | |
| 271 } | |
| 272 | |
| 273 /* Returns 1 when something is found, 0 if nothing left */ | |
| 274 int | |
| 275 OWNext(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) { | |
| 276 uint8_t bit_test, search_direction, bit_number; | |
| 277 uint8_t last_zero, rom_byte_number, next_result; | |
| 278 uint8_t rom_byte_mask; | |
| 279 uint8_t lastcrc8, crcaccum; | |
| 280 char errstr[30]; | |
| 281 | |
| 282 /* Init for search */ | |
| 283 bit_number = 1; | |
| 284 last_zero = 0; | |
| 285 rom_byte_number = 0; | |
| 286 rom_byte_mask = 1; | |
| 287 next_result = 0; | |
| 288 lastcrc8 = 0; | |
| 289 crcaccum = 0; | |
| 290 | |
| 291 /* if the last call was not the last one */ | |
| 292 if (!OW_LastDevice) { | |
| 293 /* check if reset first is requested */ | |
| 294 if (do_reset) { | |
| 295 /* reset the 1-wire | |
| 296 * if there are no parts on 1-wire, return 0 */ | |
| 297 #if OW_DEBUG | |
| 298 uart_putsP(PSTR("Resetting\n\r")); | |
| 299 #endif | |
| 300 if (OWTouchReset()) { | |
| 301 /* reset the search */ | |
| 302 OW_LastDiscrepancy = 0; | |
| 303 OW_LastFamilyDiscrepancy = 0; | |
| 304 #if OW_DEBUG | |
| 305 uart_putsP(PSTR("No devices on bus\n\r")); | |
| 306 #endif | |
| 307 return 0; | |
| 308 } | |
| 309 } | |
| 310 | |
| 311 /* If finding alarming devices issue a different command */ | |
| 312 if (alarm_only) | |
| 313 OWWriteByte(OW_SEARCH_ALRM_CMD); /* issue the alarming search command */ | |
| 314 else | |
| 315 OWWriteByte(OW_SEARCH_ROM_CMD); /* issue the search command */ | |
| 316 | |
| 317 /* pause before beginning the search */ | |
| 318 OWdelay(); | |
| 319 OWdelay(); | |
| 320 OWdelay(); | |
| 321 | |
| 322 /* loop to do the search */ | |
| 323 do { | |
| 324 /* read a bit and its compliment */ | |
| 325 bit_test = OWReadBit() << 1; | |
| 326 bit_test |= OWReadBit(); | |
| 327 | |
| 328 #if OW_DEBUG | |
| 329 sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test); | |
| 330 uart_puts(errstr); | |
| 331 #endif | |
| 332 | |
| 333 /* check for no devices on 1-wire */ | |
| 334 if (bit_test == 3) { | |
| 335 sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test); | |
| 336 uart_puts(errstr); | |
| 337 break; | |
| 338 } | |
| 339 else { | |
| 340 /* all devices coupled have 0 or 1 */ | |
| 341 if (bit_test > 0) | |
| 342 search_direction = !(bit_test & 0x01); /* bit write value for search */ | |
| 343 else { | |
| 344 /* if this discrepancy is before the Last Discrepancy | |
| 345 * on a previous OWNext then pick the same as last time */ | |
| 346 if (bit_number < OW_LastDiscrepancy) | |
| 347 search_direction = ((ROM[rom_byte_number] & rom_byte_mask) > 0); | |
| 348 else | |
| 349 /* if equal to last pick 1, if not then pick 0 */ | |
| 350 search_direction = (bit_number == OW_LastDiscrepancy); | |
| 351 | |
| 352 /* if 0 was picked then record its position in LastZero */ | |
| 353 if (search_direction == 0) { | |
| 354 last_zero = bit_number; | |
| 355 | |
| 356 /* check for Last discrepancy in family */ | |
| 357 if (last_zero < 9) | |
| 358 OW_LastFamilyDiscrepancy = last_zero; | |
| 359 } | |
| 360 } | |
| 361 | |
| 362 /* set or clear the bit in the ROM byte rom_byte_number | |
| 363 * with mask rom_byte_mask */ | |
| 364 if (search_direction == 1) | |
| 365 ROM[rom_byte_number] |= rom_byte_mask; | |
| 366 else | |
| 367 ROM[rom_byte_number] &= ~rom_byte_mask; | |
| 368 | |
| 369 /* serial number search direction write bit */ | |
| 370 OWWriteBit(search_direction); | |
| 371 | |
| 372 /* increment the byte counter bit_number | |
| 373 * and shift the mask rom_byte_mask */ | |
| 374 bit_number++; | |
| 375 rom_byte_mask <<= 1; | |
| 376 | |
| 377 /* if the mask is 0 then go to new ROM byte rom_byte_number | |
| 378 * and reset mask */ | |
| 379 if (rom_byte_mask == 0) { | |
| 380 OWCRC(ROM[rom_byte_number], &crcaccum); /* accumulate the CRC */ | |
| 381 lastcrc8 = crcaccum; | |
| 382 | |
| 383 rom_byte_number++; | |
| 384 rom_byte_mask = 1; | |
| 385 } | |
| 386 } | |
| 387 } while (rom_byte_number < 8); /* loop until through all ROM bytes 0-7 */ | |
| 388 | |
| 389 /* if the search was successful then */ | |
| 390 if (!(bit_number < 65) || lastcrc8) { | |
| 391 if (lastcrc8) { | |
| 392 sprintf_P(errstr, PSTR("Bad CRC (%d)\n\r"), lastcrc8); | |
| 393 uart_puts(errstr); | |
| 394 next_result = 0; | |
| 395 } else { | |
| 396 /* search successful so set LastDiscrepancy,LastDevice,next_result */ | |
| 397 OW_LastDiscrepancy = last_zero; | |
| 398 OW_LastDevice = (OW_LastDiscrepancy == 0); | |
| 399 #if OW_DEBUG | |
| 400 sprintf_P(errstr, PSTR("Last device = %d\n\r"), OW_LastDevice); | |
| 401 uart_puts(errstr); | |
| 402 #endif | |
| 403 next_result = 1; | |
| 404 } | |
| 405 } | |
| 406 } | |
| 407 | |
| 408 /* if no device found then reset counters so next 'next' will be | |
| 409 * like a first */ | |
| 410 if (!next_result || !ROM[0]) { | |
| 411 OW_LastDiscrepancy = 0; | |
| 412 OW_LastDevice = 0; | |
| 413 OW_LastFamilyDiscrepancy = 0; | |
| 414 next_result = 0; | |
| 415 } | |
| 416 | |
| 417 return next_result; | |
| 418 | |
| 419 } | |
| 420 | |
| 421 uint8_t PROGMEM dscrc_table[] = { | |
| 422 0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65, | |
| 423 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220, | |
| 424 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98, | |
| 425 190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255, | |
| 426 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7, | |
| 427 219, 133,103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154, | |
| 428 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36, | |
| 429 248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185, | |
| 430 140,210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113,147, 205, | |
| 431 17, 79, 173, 243, 112, 46, 204, 146, 211,141, 111, 49, 178, 236, 14, 80, | |
| 432 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82,176, 238, | |
| 433 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115, | |
| 434 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139, | |
| 435 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22, | |
| 436 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168, | |
| 437 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53 | |
| 438 }; | |
| 439 | |
| 440 void | |
| 441 OWCRC(uint8_t x, uint8_t *crc) { | |
| 442 *crc = pgm_read_byte(&dscrc_table[(*crc) ^ x]); | |
| 443 } |