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comparison 1wire.c @ 10:eb1faf51968e

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- Add some useful return values to search functions. - Remove some unecessary trailing \'s in macros - Replace some inline assembly I missed last time with C/macros.
author darius
date Mon, 12 Jul 2004 23:59:00 +0930
parents f9a085a0ba93
children 4b141cc7cbd4
comparison
equal deleted inserted replaced
9:7ed10c59ba06 10:eb1faf51968e
45 static uint8_t OW_LastDiscrepancy = 0; 45 static uint8_t OW_LastDiscrepancy = 0;
46 static uint8_t OW_LastFamilyDiscrepancy = 0; 46 static uint8_t OW_LastFamilyDiscrepancy = 0;
47 47
48 static void 48 static void
49 OWdelay(void) { 49 OWdelay(void) {
50 asm volatile ( 50 DELAY_I;
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 } 51 }
70 52
71 /*----------------------------------------------------------------------------- 53 /*-----------------------------------------------------------------------------
72 * Generate a 1-Wire reset, return 1 if no presence detect was found, 54 * Generate a 1-Wire reset, return 1 if no presence detect was found,
73 * return 0 otherwise. 55 * return 0 otherwise.
74 * (NOTE: Does not handle alarm presence from DS2404/DS1994) 56 * (NOTE: Does not handle alarm presence from DS2404/DS1994)
75 */ 57 */
76 int 58 int
77 OWTouchReset(void) { 59 OWTouchReset(void) {
78 uint8_t result; 60 DELAY_G;
79 61 OWIREOUTPORT &= ~(_BV(OWIREOUTPIN));
80 asm volatile ( 62 OWIREDDR |= _BV(OWIREOUTPIN);
81 /* Delay G (0 usec) */ 63 DELAY_H;
82 "\n\t" 64 OWIREDDR &= ~(_BV(OWIREOUTPIN));
83 /* Drive bus low */ 65 DELAY_I;
84 "cbi %[out], %[opin]\n\t" 66
85 "sbi %[ddr], %[opin]\n\t" 67 return(OWIREINPORT & _BV(OWIREINPIN) ? 1 : 0);
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 } 68 }
135 69
136 /*----------------------------------------------------------------------------- 70 /*-----------------------------------------------------------------------------
137 * Send a 1-wire write bit. 71 * Send a 1-wire write bit.
138 */ 72 */
255 } 189 }
256 190
257 /*----------------------------------------------------------------------------- 191 /*-----------------------------------------------------------------------------
258 * Search algorithm from App note 187 (and 162) 192 * Search algorithm from App note 187 (and 162)
259 * 193 *
260 * Returns 1 when something is found, 0 if nothing present 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.
261 */ 200 */
262 int 201 int
263 OWFirst(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) { 202 OWFirst(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) {
264 /* Reset state */ 203 /* Reset state */
265 OW_LastDiscrepancy = 0; 204 OW_LastDiscrepancy = 0;
272 211
273 /* Returns 1 when something is found, 0 if nothing left */ 212 /* Returns 1 when something is found, 0 if nothing left */
274 int 213 int
275 OWNext(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) { 214 OWNext(uint8_t *ROM, uint8_t do_reset, uint8_t alarm_only) {
276 uint8_t bit_test, search_direction, bit_number; 215 uint8_t bit_test, search_direction, bit_number;
277 uint8_t last_zero, rom_byte_number, next_result; 216 uint8_t last_zero, rom_byte_number, rom_byte_mask;
278 uint8_t rom_byte_mask;
279 uint8_t lastcrc8, crcaccum; 217 uint8_t lastcrc8, crcaccum;
218 int next_result;
280 char errstr[30]; 219 char errstr[30];
281 220
282 /* Init for search */ 221 /* Init for search */
283 bit_number = 1; 222 bit_number = 1;
284 last_zero = 0; 223 last_zero = 0;
285 rom_byte_number = 0; 224 rom_byte_number = 0;
286 rom_byte_mask = 1; 225 rom_byte_mask = 1;
287 next_result = 0; 226 next_result = OW_NOMODULES;
288 lastcrc8 = 0; 227 lastcrc8 = 0;
289 crcaccum = 0; 228 crcaccum = 0;
290 229
291 /* if the last call was not the last one */ 230 /* if the last call was not the last one */
292 if (!OW_LastDevice) { 231 if (!OW_LastDevice) {
302 OW_LastDiscrepancy = 0; 241 OW_LastDiscrepancy = 0;
303 OW_LastFamilyDiscrepancy = 0; 242 OW_LastFamilyDiscrepancy = 0;
304 #if OW_DEBUG 243 #if OW_DEBUG
305 uart_putsP(PSTR("No devices on bus\n\r")); 244 uart_putsP(PSTR("No devices on bus\n\r"));
306 #endif 245 #endif
307 return 0; 246 return OW_NOPRESENCE;
308 } 247 }
309 } 248 }
310 249
311 /* If finding alarming devices issue a different command */ 250 /* If finding alarming devices issue a different command */
312 if (alarm_only) 251 if (alarm_only)
330 uart_puts(errstr); 269 uart_puts(errstr);
331 #endif 270 #endif
332 271
333 /* check for no devices on 1-wire */ 272 /* check for no devices on 1-wire */
334 if (bit_test == 3) { 273 if (bit_test == 3) {
274 #if OW_DEBUG
335 sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test); 275 sprintf_P(errstr, PSTR("bit_test = %d\n\r"), bit_test);
336 uart_puts(errstr); 276 uart_puts(errstr);
337 break; 277 #endif
278 return(OW_BADWIRE);
338 } 279 }
339 else { 280 else {
340 /* all devices coupled have 0 or 1 */ 281 /* all devices coupled have 0 or 1 */
341 if (bit_test > 0) 282 if (bit_test > 0)
342 search_direction = !(bit_test & 0x01); /* bit write value for search */ 283 search_direction = !(bit_test & 0x01); /* bit write value for search */
389 /* if the search was successful then */ 330 /* if the search was successful then */
390 if (!(bit_number < 65) || lastcrc8) { 331 if (!(bit_number < 65) || lastcrc8) {
391 if (lastcrc8) { 332 if (lastcrc8) {
392 sprintf_P(errstr, PSTR("Bad CRC (%d)\n\r"), lastcrc8); 333 sprintf_P(errstr, PSTR("Bad CRC (%d)\n\r"), lastcrc8);
393 uart_puts(errstr); 334 uart_puts(errstr);
394 next_result = 0; 335 next_result = OW_BADCRC;
395 } else { 336 } else {
396 /* search successful so set LastDiscrepancy,LastDevice,next_result */ 337 /* search successful so set LastDiscrepancy,LastDevice,next_result */
397 OW_LastDiscrepancy = last_zero; 338 OW_LastDiscrepancy = last_zero;
398 OW_LastDevice = (OW_LastDiscrepancy == 0); 339 OW_LastDevice = (OW_LastDiscrepancy == 0);
399 #if OW_DEBUG 340 #if OW_DEBUG
400 sprintf_P(errstr, PSTR("Last device = %d\n\r"), OW_LastDevice); 341 sprintf_P(errstr, PSTR("Last device = %d\n\r"), OW_LastDevice);
401 uart_puts(errstr); 342 uart_puts(errstr);
402 #endif 343 #endif
403 next_result = 1; 344 next_result = OW_FOUND;
404 } 345 }
405 } 346 }
406 } 347 }
407 348
408 /* if no device found then reset counters so next 'next' will be 349 /* if no device found then reset counters so next 'next' will be
409 * like a first */ 350 * like a first */
410 if (!next_result || !ROM[0]) { 351 if (next_result != OW_FOUND || ROM[0] == 0) {
411 OW_LastDiscrepancy = 0; 352 OW_LastDiscrepancy = 0;
412 OW_LastDevice = 0; 353 OW_LastDevice = 0;
413 OW_LastFamilyDiscrepancy = 0; 354 OW_LastFamilyDiscrepancy = 0;
414 next_result = 0;
415 } 355 }
416 356
357 if (next_result == OW_FOUND && ROM[0] == 0x00)
358 next_result = OW_BADWIRE;
359
417 return next_result; 360 return next_result;
418 361
419 } 362 }
420 363
421 uint8_t PROGMEM dscrc_table[] = { 364 uint8_t PROGMEM dscrc_table[] = {