Mercurial > ~darius > hgwebdir.cgi > stm32temp
annotate 1wire.c @ 48:2f336d212c74
Ignore more emacs crap.
| author | Daniel O'Connor <darius@dons.net.au> |
|---|---|
| date | Wed, 03 Apr 2013 23:33:47 +1030 |
| parents | 969bb070b181 |
| children | cc998b0b2bae |
| rev | line source |
|---|---|
| 13 | 1 /* |
| 2 * Various 1 wire routines | |
| 3 * Search routine is copied from the Dallas owpd library with mods | |
| 4 * available from here http://www.ibutton.com/software/1wire/wirekit.html | |
| 5 * | |
| 6 * $Id$ | |
| 7 * | |
| 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 /* | |
| 34 * No user servicable parts inside | |
| 35 * | |
| 36 * Modify 1wire-config.h | |
| 37 */ | |
| 38 | |
| 39 #include <stdio.h> | |
| 40 #include <stdint.h> | |
| 41 #include "1wire-config.h" | |
| 42 #include "1wire.h" | |
| 43 | |
| 44 static uint8_t OW_LastDevice = 0; | |
| 45 static uint8_t OW_LastDiscrepancy = 0; | |
| 46 static uint8_t OW_LastFamilyDiscrepancy = 0; | |
| 47 | |
| 48 const PROGMEM char *OWProgROM_Status[] = { | |
| 49 "OK", | |
| 50 "no HW support", | |
| 51 "Invalid params", | |
| 52 "module missing/broken" | |
| 53 }; | |
| 54 | |
| 55 /*----------------------------------------------------------------------------- | |
| 56 * Configure the IO port as we need | |
| 57 */ | |
| 58 void | |
| 59 OWInit(void) { | |
| 60 OWBUSINIT(); | |
| 61 OWSETBUSHIGH(); | |
| 62 } | |
| 63 | |
| 64 /*----------------------------------------------------------------------------- | |
| 65 * Generate a 1-Wire reset, return 0 if presence pulse was found, 1 if it | |
| 66 * wasn't, or 2 if the line appears to be being held low. | |
| 67 * | |
| 68 * (NOTE: Does not handle alarm presence from DS2404/DS1994) | |
| 69 */ | |
| 70 uint8_t | |
| 71 OWTouchReset(void) { | |
| 72 uint8_t i; | |
| 73 | |
| 74 OWDELAY_G; | |
| 75 | |
| 76 /* Check the bus isn't being held low (ie it's broken) Do it after | |
| 77 * the delay so we guarantee we don't see a slave from a previous | |
| 78 * comms attempt | |
| 79 */ | |
| 80 #if 1 | |
| 81 OWSETREAD(); | |
| 82 if(OWREADBUS() == 0) | |
| 83 return 2; | |
| 84 #endif | |
| 85 | |
| 86 OWSETBUSLOW(); | |
| 87 OWDELAY_H; | |
| 88 OWSETBUSHIGH(); | |
| 89 OWDELAY_I; | |
| 90 | |
| 91 OWSETREAD(); | |
| 92 i = OWREADBUS(); | |
| 93 | |
| 94 OWDELAY_J; | |
| 95 return(i); | |
| 96 } | |
| 97 | |
| 98 /*----------------------------------------------------------------------------- | |
| 99 * Send a 1-wire write bit. | |
| 100 */ | |
| 101 void | |
| 102 OWWriteBit(uint8_t bit) { | |
| 103 OWDELAY_I; | |
| 104 | |
| 105 if (bit) { | |
| 106 OWSETBUSLOW(); | |
| 107 OWDELAY_A; | |
| 108 OWSETBUSHIGH(); | |
| 109 OWDELAY_B; | |
| 110 } else { | |
| 111 OWSETBUSLOW(); | |
| 112 OWDELAY_C; | |
| 113 OWSETBUSHIGH(); | |
| 114 OWDELAY_D; | |
| 115 } | |
| 116 } | |
| 117 | |
| 118 /*----------------------------------------------------------------------------- | |
| 119 * Read a bit from the 1-wire bus and return it. | |
| 120 */ | |
| 121 uint8_t | |
| 122 OWReadBit(void) { | |
| 123 uint8_t i; | |
| 124 | |
| 125 OWDELAY_I; | |
| 126 | |
| 127 OWSETBUSLOW(); | |
| 128 OWDELAY_A; | |
| 129 OWSETBUSHIGH(); | |
| 130 OWDELAY_E; | |
| 131 OWSETREAD(); | |
| 132 i = OWREADBUS(); | |
| 133 OWDELAY_F; | |
| 134 return(i); | |
| 135 } | |
| 136 | |
| 137 /*----------------------------------------------------------------------------- | |
| 138 * Write a byte to the 1-wire bus | |
| 139 */ | |
| 140 void | |
| 141 OWWriteByte(uint8_t data) { | |
| 142 uint8_t i; | |
| 143 | |
| 144 /* Send LSB first */ | |
| 145 for (i = 0; i < 8; i++) { | |
| 146 OWWriteBit(data & 0x01); | |
| 147 data >>= 1; | |
| 148 } | |
| 149 } | |
| 150 | |
| 151 /*----------------------------------------------------------------------------- | |
| 152 * Read a byte from the 1-wire bus | |
| 153 */ | |
| 154 uint8_t | |
| 155 OWReadByte(void) { | |
| 156 int i, result = 0; | |
| 157 | |
| 158 for (i = 0; i < 8; i++) { | |
| 159 result >>= 1; | |
| 160 if (OWReadBit()) | |
| 161 result |= 0x80; | |
| 162 } | |
| 163 return(result); | |
| 164 } | |
| 165 | |
| 166 /*----------------------------------------------------------------------------- | |
| 167 * Write a 1-wire data byte and return the sampled result. | |
| 168 */ | |
| 169 uint8_t | |
| 170 OWTouchByte(uint8_t data) { | |
| 171 uint8_t i, result = 0; | |
| 172 | |
| 173 for (i = 0; i < 8; i++) { | |
| 174 result >>= 1; | |
| 175 | |
| 176 /* If sending a 1 then read a bit, otherwise write a 0 */ | |
| 177 if (data & 0x01) { | |
| 178 if (OWReadBit()) | |
| 179 result |= 0x80; | |
| 180 } else | |
| 181 OWWriteBit(0); | |
| 182 | |
| 183 data >>= 1; | |
| 184 } | |
| 185 | |
| 186 return(result); | |
| 187 } | |
| 188 | |
| 189 /*----------------------------------------------------------------------------- | |
| 190 * Write a block of bytes to the 1-wire bus and return the sampled result in | |
| 191 * the same buffer | |
| 192 */ | |
| 193 void | |
| 194 OWBlock(uint8_t *data, int len) { | |
| 195 int i; | |
| 196 | |
| 197 for (i = 0; i < len; i++) | |
| 198 data[i] = OWTouchByte(data[i]); | |
| 199 } | |
| 200 | |
| 201 | |
| 202 /*----------------------------------------------------------------------------- | |
| 203 * Send a 1 wire command to a device, or all if no ROM ID provided | |
| 204 */ | |
| 205 void | |
| 206 OWSendCmd(uint8_t *ROM, uint8_t cmd) { | |
| 207 uint8_t i; | |
| 208 | |
| 209 OWTouchReset(); | |
| 210 | |
| 211 if (ROM == NULL) | |
| 212 OWWriteByte(OW_SKIP_ROM_CMD); | |
| 213 else { | |
| 214 OWWriteByte(OW_MATCH_ROM_CMD); | |
| 215 for (i = 0; i < 8; i++) | |
| 216 OWWriteByte(ROM[i]); | |
| 217 } | |
| 218 OWWriteByte(cmd); | |
| 219 } | |
| 220 | |
| 221 /*----------------------------------------------------------------------------- | |
| 222 * Search algorithm from App note 187 (and 162) | |
| 223 * | |
| 224 * OWFirst/OWNext return.. | |
| 225 * 1 when something is found, | |
| 226 * 0 no more modules | |
| 227 * -1 if no presence pulse, | |
| 228 * -2 if bad CRC, | |
| 229 * -3 if bad wiring. | |
| 230 */ | |
| 231 uint8_t | |
| 232 OWFirst(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) { | |
| 233 /* Reset state */ | |
| 234 OW_LastDiscrepancy = 0; | |
| 235 OW_LastDevice = 0; | |
| 236 OW_LastFamilyDiscrepancy = 0; | |
| 237 | |
| 238 /* Go looking */ | |
| 239 return (OWNext(ROM, do_reset, alarm_only)); | |
| 240 } | |
| 241 | |
| 242 /* Returns 1 when something is found, 0 if nothing left */ | |
| 243 uint8_t | |
| 244 OWNext(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) { | |
| 245 uint8_t bit_test, search_direction, bit_number; | |
| 246 uint8_t last_zero, rom_byte_number, rom_byte_mask; | |
| 247 uint8_t lastcrc8, crcaccum; | |
| 248 int8_t next_result; | |
| 249 | |
| 250 /* Init for search */ | |
| 251 bit_number = 1; | |
| 252 last_zero = 0; | |
| 253 rom_byte_number = 0; | |
| 254 rom_byte_mask = 1; | |
| 255 next_result = OW_NOMODULES; | |
| 256 lastcrc8 = 0; | |
| 257 crcaccum = 0; | |
| 258 | |
| 259 /* if the last call was not the last one */ | |
| 260 if (!OW_LastDevice) { | |
| 261 /* check if reset first is requested */ | |
| 262 if (do_reset) { | |
| 263 /* reset the 1-wire | |
| 264 * if there are no parts on 1-wire, return 0 */ | |
| 265 OWPUTSP(PSTR("Resetting\r\n")); | |
| 266 switch (OWTouchReset()) { | |
| 267 case 0: | |
| 268 OWPUTSP(PSTR("Found device(s)\r\n")); | |
| 269 break; | |
| 270 | |
| 271 case 1: | |
| 272 /* reset the search */ | |
| 273 OW_LastDiscrepancy = 0; | |
| 274 OW_LastFamilyDiscrepancy = 0; | |
| 275 OWPUTSP(PSTR("No devices on bus\r\n")); | |
| 276 return OW_NOPRESENCE; | |
| 277 break; | |
| 278 | |
| 279 case 2: | |
| 280 /* reset the search */ | |
| 281 OW_LastDiscrepancy = 0; | |
| 282 OW_LastFamilyDiscrepancy = 0; | |
| 283 OWPUTSP(PSTR("Bus appears to be being held low\r\n")); | |
| 284 return OW_BADWIRE; | |
| 285 break; | |
| 286 | |
| 287 } | |
| 288 } | |
| 289 | |
| 290 /* If finding alarming devices issue a different command */ | |
| 291 if (alarm_only) | |
| 292 OWWriteByte(OW_SEARCH_ALRM_CMD); /* issue the alarming search command */ | |
| 293 else | |
| 294 OWWriteByte(OW_SEARCH_ROM_CMD); /* issue the search command */ | |
| 295 | |
| 296 /* pause before beginning the search */ | |
| 297 OWDELAY_I; | |
| 298 OWDELAY_I; | |
| 299 OWDELAY_I; | |
| 300 | |
| 301 /* loop to do the search */ | |
| 302 do { | |
| 303 /* read a bit and its compliment */ | |
| 304 bit_test = OWReadBit() << 1; | |
| 305 bit_test |= OWReadBit(); | |
| 306 | |
| 307 OWPRINTFP(PSTR("bit_test = %d\r\n"), bit_test); | |
| 308 | |
| 309 /* check for no devices on 1-wire */ | |
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310 if (bit_test == 3) |
| 13 | 311 return(OW_BADWIRE); |
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312 |
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313 /* all devices coupled have 0 or 1 */ |
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314 if (bit_test > 0) |
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315 search_direction = !(bit_test & 0x01); /* bit write value for search */ |
| 13 | 316 else { |
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317 /* if this discrepancy is before the Last Discrepancy |
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318 * on a previous OWNext then pick the same as last time */ |
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319 if (bit_number < OW_LastDiscrepancy) |
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320 search_direction = ((ROM[rom_byte_number] & rom_byte_mask) > 0); |
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321 else |
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322 /* if equal to last pick 1, if not then pick 0 */ |
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323 search_direction = (bit_number == OW_LastDiscrepancy); |
| 13 | 324 |
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325 /* if 0 was picked then record its position in LastZero */ |
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326 if (search_direction == 0) { |
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327 last_zero = bit_number; |
| 13 | 328 |
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329 /* check for Last discrepancy in family */ |
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330 if (last_zero < 9) |
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331 OW_LastFamilyDiscrepancy = last_zero; |
| 13 | 332 } |
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333 } |
| 13 | 334 |
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335 /* set or clear the bit in the ROM byte rom_byte_number |
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336 * with mask rom_byte_mask */ |
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337 if (search_direction == 1) |
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338 ROM[rom_byte_number] |= rom_byte_mask; |
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339 else |
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340 ROM[rom_byte_number] &= ~rom_byte_mask; |
| 13 | 341 |
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342 /* serial number search direction write bit */ |
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343 OWWriteBit(search_direction); |
| 13 | 344 |
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345 /* increment the byte counter bit_number |
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346 * and shift the mask rom_byte_mask */ |
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347 bit_number++; |
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348 rom_byte_mask <<= 1; |
| 13 | 349 |
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350 /* if the mask is 0 then go to new ROM byte rom_byte_number |
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351 * and reset mask */ |
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352 if (rom_byte_mask == 0) { |
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353 OWCRC(ROM[rom_byte_number], &crcaccum); /* accumulate the CRC */ |
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354 lastcrc8 = crcaccum; |
| 13 | 355 |
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356 rom_byte_number++; |
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357 rom_byte_mask = 1; |
| 13 | 358 } |
| 359 } while (rom_byte_number < 8); /* loop until through all ROM bytes 0-7 */ | |
| 360 | |
| 361 /* if the search was successful then */ | |
| 362 if (!(bit_number < 65) || lastcrc8) { | |
| 363 if (lastcrc8) { | |
| 364 OWPRINTFP(PSTR("Bad CRC (%d)\r\n"), lastcrc8); | |
| 365 next_result = OW_BADCRC; | |
| 366 } else { | |
| 367 /* search successful so set LastDiscrepancy,LastDevice,next_result */ | |
| 368 OW_LastDiscrepancy = last_zero; | |
| 369 OW_LastDevice = (OW_LastDiscrepancy == 0); | |
| 370 OWPRINTFP(PSTR("Last device = %d\r\n"), OW_LastDevice); | |
| 371 next_result = OW_FOUND; | |
| 372 } | |
| 373 } | |
| 374 } | |
| 375 | |
| 376 /* if no device found then reset counters so next 'next' will be | |
| 377 * like a first */ | |
| 378 if (next_result != OW_FOUND || ROM[0] == 0) { | |
| 379 OW_LastDiscrepancy = 0; | |
| 380 OW_LastDevice = 0; | |
| 381 OW_LastFamilyDiscrepancy = 0; | |
| 382 } | |
| 383 | |
| 384 if (next_result == OW_FOUND && ROM[0] == 0x00) | |
| 385 next_result = OW_BADWIRE; | |
| 386 | |
| 387 return next_result; | |
| 388 | |
| 389 } | |
| 390 | |
| 391 uint8_t PROGMEM dscrc_table[] = { | |
| 392 0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65, | |
| 393 157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220, | |
| 394 35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98, | |
| 395 190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255, | |
| 396 70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7, | |
| 397 219, 133,103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154, | |
| 398 101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36, | |
| 399 248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185, | |
| 400 140,210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113,147, 205, | |
| 401 17, 79, 173, 243, 112, 46, 204, 146, 211,141, 111, 49, 178, 236, 14, 80, | |
| 402 175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82,176, 238, | |
| 403 50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115, | |
| 404 202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139, | |
| 405 87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22, | |
| 406 233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168, | |
| 407 116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53 | |
| 408 }; | |
| 409 | |
| 410 /*----------------------------------------------------------------------------- | |
| 411 * Update *crc based on the value of x | |
| 412 */ | |
| 413 void | |
| 414 OWCRC(uint8_t x, uint8_t *crc) { | |
| 415 *crc = pgm_read_byte(&dscrc_table[(*crc) ^ x]); | |
| 416 } | |
| 417 | |
| 418 /*----------------------------------------------------------------------------- | |
| 419 * Program a DS2502's memory | |
| 420 * | |
| 421 * Arguments | |
| 422 * ROM - ROM ID (or NULL to send SKIP_ROM) | |
| 423 * start - Start address (bytes) | |
| 424 * len - Length of data to write | |
| 425 * data - Data to write | |
| 426 * exact - If true, only accept exact matches for programming, | |
| 427 * otherwise only ensure the bits we requested were | |
| 428 * programmed [to 0] | |
| 429 * status - If true program status rather than memory | |
| 430 * | |
| 431 * Returns.. | |
| 432 * 0 if all is OK | |
| 433 * 1 if the programming is not possible | |
| 434 * 2 if the parameters were invalid | |
| 435 * 3 if the DS2502 didn't respond appropriately (also happens if the | |
| 436 * module doesn't exist) | |
| 437 */ | |
| 438 #if defined(OWSETVPPON) && defined(OWSETVPPOFF) | |
| 439 uint8_t | |
| 440 OWProgROM(uint8_t *ROM, uint8_t start, uint8_t len, uint8_t *data, uint8_t exact, uint8_t status) { | |
| 441 uint8_t crc, i, tmp; | |
| 442 | |
| 443 /* Stupid programmer detection */ | |
| 444 if (status) { | |
| 445 if (start + len > 3) | |
| 446 return(2); | |
| 447 } else { | |
| 448 if (start + len > 127) | |
| 449 return(2); | |
| 450 } | |
| 451 | |
| 452 if (len < 1) | |
| 453 return(2); | |
| 454 | |
| 455 OWDELAY_I; | |
| 456 if (OWTouchReset() != 0) { | |
| 457 cons_putsP(PSTR("No presence pulse\r\n")); | |
| 458 return(3); | |
| 459 } | |
| 460 | |
| 461 crc = 0; | |
| 462 | |
| 463 /* Send the command */ | |
| 464 if (status) { | |
| 465 OWSendCmd(ROM, OW_WRITE_STATUS); | |
| 466 OWCRC(OW_WRITE_STATUS, &crc); | |
| 467 } else { | |
| 468 OWSendCmd(ROM, OW_WRITE_MEMORY); | |
| 469 OWCRC(OW_WRITE_MEMORY, &crc); | |
| 470 } | |
| 471 | |
| 472 /* And the start address | |
| 473 * (2 bytes even though one would do) | |
| 474 */ | |
| 475 OWWriteByte(start); | |
| 476 OWCRC(start, &crc); | |
| 477 | |
| 478 OWWriteByte(0x00); | |
| 479 OWCRC(0x00, &crc); | |
| 480 | |
| 481 for (i = 0; i < len; i++) { | |
| 482 cons_putsP(PSTR("Programming ")); | |
| 483 cons_puts_hex(data[i]); | |
| 484 cons_putsP(PSTR(" to ")); | |
| 485 cons_puts_hex(start + i); | |
| 486 cons_putsP(PSTR("\r\n")); | |
| 487 | |
| 488 OWWriteByte(data[i]); | |
| 489 OWCRC(data[i], &crc); | |
| 490 | |
| 491 tmp = OWReadByte(); | |
| 492 | |
| 493 if (crc != tmp) { | |
| 494 cons_putsP(PSTR("CRC mismatch ")); | |
| 495 cons_puts_hex(crc); | |
| 496 cons_putsP(PSTR(" vs ")); | |
| 497 cons_puts_hex(tmp); | |
| 498 cons_putsP(PSTR("\r\n")); | |
| 499 | |
| 500 OWTouchReset(); | |
| 501 return(3); | |
| 502 } | |
| 503 | |
| 504 OWSETVPPON(); | |
| 505 OWDELAY_H; | |
| 506 OWSETVPPOFF(); | |
| 507 | |
| 508 tmp = OWReadByte(); | |
| 509 | |
| 510 /* Check the bits we turned off are off */ | |
| 511 /* | |
| 512 for (i = 0; i < 8; i++) | |
| 513 if (!(data[i] & 1 << i) && (tmp & 1 << i)) | |
| 514 return(-3); | |
| 515 */ | |
| 516 if ((!data[i] & tmp) != 0) { | |
| 517 cons_putsP(PSTR("Readback mismatch ")); | |
| 518 cons_puts_hex(data[i]); | |
| 519 cons_putsP(PSTR(" vs ")); | |
| 520 cons_puts_hex(data[i]); | |
| 521 cons_putsP(PSTR("\r\n")); | |
| 522 | |
| 523 OWTouchReset(); | |
| 524 return(3); | |
| 525 } | |
| 526 | |
| 527 /* The DS2502 loads it's CRC register with the address of the | |
| 528 * next byte */ | |
| 529 crc = 0; | |
| 530 OWCRC(start + i + 1, &crc); | |
| 531 } | |
| 532 | |
| 533 return(0); | |
| 534 } | |
| 535 #else | |
| 536 uint8_t | |
| 537 OWProgROM(uint8_t *ROM __attribute((unused)), uint8_t start __attribute((unused)), uint8_t len __attribute((unused)), uint8_t *data __attribute((unused)), uint8_t exact __attribute((unused)), uint8_t status __attribute((unused))) { | |
| 538 return(1); | |
| 539 } | |
| 540 #endif | |
| 541 | |
| 542 /* | |
| 543 * OWGetTemp | |
| 544 * | |
| 545 * Get the temperature from a 1wire bus module | |
| 546 * | |
| 547 * Returns temperature in hundredths of a degree or OW_TEMP_xxx on | |
| 548 * error. | |
| 549 */ | |
| 550 int16_t | |
| 551 OWGetTemp(uint8_t *ROM) { | |
| 552 int8_t i; | |
| 553 uint8_t crc, buf[9]; | |
| 554 int16_t temp; | |
| 555 int16_t tfrac; | |
| 556 | |
| 557 if (ROM[0] != OW_FAMILY_TEMP) | |
| 558 return OW_TEMP_WRONG_FAM; | |
| 559 | |
| 560 OWSendCmd(ROM, OW_CONVERTT_CMD); | |
| 561 | |
| 562 i = 0; | |
| 563 | |
| 564 /* Wait for the conversion */ | |
| 565 while (OWReadBit() == 0) | |
| 566 i = 1; | |
| 567 | |
| 568 /* Check that we talked to a module and it did something */ | |
| 569 if (i == 0) { | |
| 570 return OW_TEMP_NO_ROM; | |
| 571 } | |
| 572 | |
| 573 OWSendCmd(ROM, OW_RD_SCR_CMD); | |
| 574 crc = 0; | |
| 575 for (i = 0; i < 8; i++) { | |
| 576 buf[i] = OWReadByte(); | |
| 577 OWCRC(buf[i], &crc); | |
| 578 } | |
| 579 buf[i] = OWReadByte(); | |
| 580 if (crc != buf[8]) | |
| 581 return OW_TEMP_CRC_ERR; | |
| 582 temp = buf[0]; | |
| 583 if (buf[1] & 0x80) | |
| 584 temp -= 256; | |
| 585 | |
| 586 /* Chop off 0.5 degree bit */ | |
| 587 temp >>= 1; | |
| 588 | |
| 589 /* Calulate the fractional remainder */ | |
| 590 tfrac = buf[7] - buf[6]; | |
| 591 | |
| 592 /* Work in 100'th of degreess to save on floats */ | |
| 593 tfrac *= (int16_t)100; | |
| 594 | |
| 595 /* Divide by count */ | |
| 596 tfrac /= buf[7]; | |
| 597 | |
| 598 /* Subtract 0.25 deg from temp */ | |
| 599 tfrac += 75; | |
| 600 if (tfrac < 100) | |
| 601 temp--; | |
| 602 else | |
| 603 tfrac -= 100; | |
| 604 | |
| 605 i = temp; | |
| 606 temp *= 100; | |
| 607 temp += tfrac; | |
| 608 | |
| 609 return(temp); | |
| 610 } | |
| 611 | |
| 612 /* | |
| 613 * OWTempStatusStr | |
| 614 * | |
| 615 * Return a string for each OW_TEMP_xxx error code | |
| 616 * | |
| 617 * shrt = 1 returns short strings | |
| 618 * | |
| 619 */ | |
| 620 const char * | |
| 621 OWTempStatusStr(int16_t val, uint8_t shrt) { | |
| 622 if (val > OW_TEMP_BADVAL) { | |
| 623 if (shrt) | |
| 624 return PSTR("OK"); | |
| 625 else | |
| 626 return PSTR("OK"); | |
| 627 } | |
| 628 | |
| 629 switch (val) { | |
| 630 case OW_TEMP_WRONG_FAM: | |
| 631 if (shrt) | |
| 632 return PSTR("WrFam"); | |
| 633 else | |
| 634 return PSTR("Wrong family"); | |
| 635 break; | |
| 636 case OW_TEMP_CRC_ERR: | |
| 637 if (shrt) | |
| 638 return PSTR("CRCErr"); | |
| 639 else | |
| 640 return PSTR("CRC Error"); | |
| 641 break; | |
| 642 case OW_TEMP_NO_ROM: | |
| 643 if (shrt) | |
| 644 return PSTR("NoROM"); | |
| 645 else | |
| 646 return PSTR("ROM did not reply"); | |
| 647 break; | |
| 648 default: | |
| 649 if (shrt) | |
| 650 return PSTR("???"); | |
| 651 else | |
| 652 return PSTR("Unknown error code"); | |
| 653 break; | |
| 654 } | |
| 655 } |