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comparison Small_CPU/Src/pressure.c @ 38:5f11787b4f42
include in ostc4 repository
author | heinrichsweikamp |
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date | Sat, 28 Apr 2018 11:52:34 +0200 |
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children | f11f0bf6ef2d |
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1 /** | |
2 ****************************************************************************** | |
3 * @file pressure.c | |
4 * @author heinrichs weikamp gmbh | |
5 * @date 2014 | |
6 * @version V0.0.2 | |
7 * @since 20-Oct-2016 | |
8 * @brief | |
9 * | |
10 @verbatim | |
11 ============================================================================== | |
12 ##### How to use ##### | |
13 ============================================================================== | |
14 V0.0.2 18-Oct-2016 pressure_calculation_AN520_004_mod_MS5803_30BA__09_2015 | |
15 | |
16 @endverbatim | |
17 ****************************************************************************** | |
18 * @attention | |
19 * | |
20 * <h2><center>© COPYRIGHT(c) 2016 heinrichs weikamp</center></h2> | |
21 * | |
22 ****************************************************************************** | |
23 */ | |
24 | |
25 | |
26 | |
27 /* surface time | |
28 the last 30 minutes will be saved once per minute in a endless loop | |
29 at the beginning of a dive the oldest value will be used | |
30 */ | |
31 | |
32 | |
33 #include "pressure.h" | |
34 #include "i2c.h" | |
35 #include "rtc.h" | |
36 | |
37 #define CMD_RESET 0x1E // ADC reset command | |
38 #define CMD_ADC_READ 0x00 // ADC read command | |
39 #define CMD_ADC_CONV 0x40 // ADC conversion command | |
40 #define CMD_ADC_D1 0x00 // ADC D1 conversion | |
41 #define CMD_ADC_D2 0x10 // ADC D2 conversion | |
42 #define CMD_ADC_256 0x00 // ADC OSR=256 | |
43 #define CMD_ADC_512 0x02 // ADC OSR=512 | |
44 #define CMD_ADC_1024 0x04 // ADC OSR=1024 | |
45 #define CMD_ADC_2048 0x06 // ADC OSR=2056 | |
46 #define CMD_ADC_4096 0x08 // ADC OSR=4096 | |
47 #define CMD_PROM_RD 0xA0 // Prom read command | |
48 | |
49 | |
50 //uint16_t get_ci(uint8_t cmd); | |
51 //uint8_t get_ci_crc(void); | |
52 uint16_t get_ci_by_coef_num(uint8_t coef_num); | |
53 void pressure_calculation_new(void); | |
54 void pressure_calculation_old(void); | |
55 void pressure_calculation_AN520_004_mod_MS5803_30BA__09_2015(void); | |
56 | |
57 uint8_t crc4(uint16_t n_prom[]); | |
58 | |
59 HAL_StatusTypeDef pressure_sensor_get_data(void); | |
60 uint32_t get_adc(void); | |
61 uint8_t pressureSensorInitSuccess = 0; | |
62 | |
63 //void test_calculation(void); | |
64 | |
65 uint16_t C[8] = { 1 }; | |
66 uint32_t D1 = 1; | |
67 uint32_t D2 = 1; | |
68 uint8_t n_crc; | |
69 | |
70 int64_t C5_x_2p8 = 1; | |
71 int64_t C2_x_2p16 = 1; | |
72 int64_t C1_x_2p15 = 1; | |
73 | |
74 /* | |
75 short C2plus10000 = -1; | |
76 short C3plus200 = -1; | |
77 short C4minus250 = -1; | |
78 short UT1 = -1; | |
79 short C6plus100 = -1; | |
80 */ | |
81 | |
82 float ambient_temperature = 0; | |
83 float ambient_pressure_mbar = 0; | |
84 float surface_pressure_mbar = 1000; | |
85 float surface_ring_mbar[31] = { 0 }; | |
86 | |
87 uint8_t secondCounterSurfaceRing = 0; | |
88 | |
89 float get_temperature(void) | |
90 { | |
91 return ambient_temperature; | |
92 } | |
93 | |
94 //float test = 1000; | |
95 | |
96 float get_pressure_mbar(void) | |
97 { | |
98 // return test; | |
99 return ambient_pressure_mbar; | |
100 } | |
101 | |
102 | |
103 float get_surface_mbar(void) | |
104 { | |
105 return surface_pressure_mbar; | |
106 } | |
107 | |
108 | |
109 void init_surface_ring(void) | |
110 { | |
111 surface_ring_mbar[0] = 0; | |
112 for(int i=1; i<31; i++) | |
113 surface_ring_mbar[i] = ambient_pressure_mbar; | |
114 surface_pressure_mbar = ambient_pressure_mbar; | |
115 } | |
116 | |
117 | |
118 /* the ring has one place with 0 | |
119 * after that comes the oldest value | |
120 * the new pressure is written in this hole | |
121 * the oldest value is read and then the new hole | |
122 */ | |
123 void update_surface_pressure(uint8_t call_rhythm_seconds) | |
124 { | |
125 secondCounterSurfaceRing += call_rhythm_seconds; | |
126 | |
127 if(secondCounterSurfaceRing < 60) | |
128 return; | |
129 | |
130 secondCounterSurfaceRing = 0; | |
131 | |
132 int hole; | |
133 for(hole=30;hole>0;hole--) | |
134 if(surface_ring_mbar[hole] == 0) { break; } | |
135 | |
136 surface_ring_mbar[hole] = ambient_pressure_mbar; | |
137 | |
138 hole++; | |
139 if(hole > 30) | |
140 hole = 0; | |
141 surface_pressure_mbar = surface_ring_mbar[hole]; | |
142 surface_ring_mbar[hole] = 0; | |
143 } | |
144 | |
145 | |
146 float demo_modify_temperature_helper(float bottom_mbar_diff_to_surface) | |
147 { | |
148 const float temperature_surface = 31.0; | |
149 const float temperature_bottom = 14.0; | |
150 | |
151 const float temperature_difference = temperature_bottom - temperature_surface; | |
152 | |
153 // range 0.0 - 1.0 | |
154 float position_now = (ambient_pressure_mbar - surface_pressure_mbar) / bottom_mbar_diff_to_surface; | |
155 | |
156 if(position_now <= 0) | |
157 return temperature_surface; | |
158 | |
159 if(position_now >= 1) | |
160 return temperature_bottom; | |
161 | |
162 return temperature_surface + (temperature_difference * position_now); | |
163 } | |
164 | |
165 | |
166 uint32_t demo_modify_temperature_and_pressure(int32_t divetime_in_seconds, uint8_t subseconds, float ceiling_mbar) | |
167 { | |
168 | |
169 const float descent_rate = 4000/60; | |
170 const float ascent_rate = 1000/60; | |
171 const uint32_t seconds_descend = (1 * 60) + 30; | |
172 const uint32_t turbo_seconds_at_bottom_start = (0 * 60) + 0; | |
173 const uint32_t seconds_descend_and_bottomtime = seconds_descend + turbo_seconds_at_bottom_start + (2 * 60) + 0; | |
174 uint32_t time_elapsed_in_seconds; | |
175 static float ambient_pressure_mbar_memory = 0; | |
176 static uint32_t time_last_call = 0; | |
177 | |
178 if(divetime_in_seconds <= seconds_descend) | |
179 { | |
180 ambient_pressure_mbar = (divetime_in_seconds * descent_rate) + ((float)(subseconds) * descent_rate) + surface_pressure_mbar; | |
181 ambient_temperature = demo_modify_temperature_helper(descent_rate * seconds_descend); | |
182 | |
183 time_last_call = divetime_in_seconds; | |
184 return 0; | |
185 } | |
186 else | |
187 if(divetime_in_seconds <= seconds_descend + turbo_seconds_at_bottom_start) | |
188 { | |
189 ambient_pressure_mbar = (seconds_descend * descent_rate) + surface_pressure_mbar; | |
190 ambient_temperature = demo_modify_temperature_helper(descent_rate * seconds_descend); | |
191 ambient_pressure_mbar_memory = ambient_pressure_mbar; | |
192 time_last_call = divetime_in_seconds; | |
193 return turbo_seconds_at_bottom_start; | |
194 } | |
195 else | |
196 if(divetime_in_seconds <= seconds_descend_and_bottomtime) | |
197 { | |
198 ambient_pressure_mbar = (seconds_descend * descent_rate) + surface_pressure_mbar; | |
199 ambient_temperature = demo_modify_temperature_helper(descent_rate * seconds_descend); | |
200 ambient_pressure_mbar_memory = ambient_pressure_mbar; | |
201 time_last_call = divetime_in_seconds; | |
202 return 0; | |
203 } | |
204 else | |
205 { | |
206 time_elapsed_in_seconds = divetime_in_seconds - time_last_call; | |
207 ambient_pressure_mbar = ambient_pressure_mbar_memory - time_elapsed_in_seconds * ascent_rate; | |
208 | |
209 if(ambient_pressure_mbar < surface_pressure_mbar) | |
210 ambient_pressure_mbar = surface_pressure_mbar; | |
211 else if(ambient_pressure_mbar < ceiling_mbar) | |
212 ambient_pressure_mbar = ceiling_mbar; | |
213 | |
214 ambient_temperature = demo_modify_temperature_helper(descent_rate * seconds_descend); | |
215 ambient_pressure_mbar_memory = ambient_pressure_mbar; | |
216 time_last_call = divetime_in_seconds; | |
217 return 0; | |
218 } | |
219 } | |
220 | |
221 | |
222 /* called just once on power on */ | |
223 void init_pressure_DRx(void) | |
224 { | |
225 uint8_t resetCommand[1] = {0x1E}; | |
226 | |
227 I2C_Master_Transmit( DEVICE_PRESSURE, resetCommand, 1); | |
228 HAL_Delay(3); | |
229 | |
230 C[1] = get_ci_by_coef_num(0x02); | |
231 C[2] = get_ci_by_coef_num(0x04); | |
232 C[3] = get_ci_by_coef_num(0x06); | |
233 C[4] = get_ci_by_coef_num(0x08); | |
234 C[5] = get_ci_by_coef_num(0x0A); | |
235 C[6] = get_ci_by_coef_num(0x0C); | |
236 | |
237 C5_x_2p8 = C[5] * 256; | |
238 C2_x_2p16 = C[2] * 65536; | |
239 C1_x_2p15 = C[1] * 32768; | |
240 pressure_update(); | |
241 } | |
242 | |
243 uint8_t is_init_pressure_done(void) | |
244 { | |
245 return pressureSensorInitSuccess; | |
246 } | |
247 | |
248 uint8_t init_pressure(void) | |
249 { | |
250 uint8_t buffer[1]; | |
251 buffer[0] = 0x1e; | |
252 uint8_t retValue = 0xFF; | |
253 | |
254 | |
255 retValue = I2C_Master_Transmit( DEVICE_PRESSURE, buffer, 1); | |
256 if(retValue != HAL_OK) | |
257 { | |
258 return (HAL_StatusTypeDef)retValue; | |
259 } | |
260 HAL_Delay(3); | |
261 | |
262 for(uint8_t i=0;i<8;i++) | |
263 { | |
264 C[i] = get_ci_by_coef_num(i); | |
265 } | |
266 n_crc = crc4(C); // no evaluation at the moment hw 151026 | |
267 | |
268 C5_x_2p8 = C[5] * 256; | |
269 C2_x_2p16 = C[2] * 65536; | |
270 C1_x_2p15 = C[1] * 32768; | |
271 | |
272 if(I2C1_Status() == HAL_OK) | |
273 { | |
274 pressureSensorInitSuccess = 1; | |
275 } | |
276 return pressure_update(); | |
277 } | |
278 | |
279 | |
280 uint32_t get_adc(void) | |
281 { | |
282 uint8_t buffer[1]; | |
283 uint8_t resivebuf[4]; | |
284 uint32_t answer = 0; | |
285 // | |
286 buffer[0] = 0x00; // Get ADC | |
287 I2C_Master_Transmit( DEVICE_PRESSURE, buffer, 1); | |
288 I2C_Master_Receive( DEVICE_PRESSURE, resivebuf, 4); | |
289 resivebuf[3] = 0; | |
290 answer = 256*256 *(uint32_t)resivebuf[0] + 256 * (uint32_t)resivebuf[1] + (uint32_t)resivebuf[2]; | |
291 | |
292 return answer; | |
293 } | |
294 | |
295 | |
296 uint16_t get_ci_by_coef_num(uint8_t coef_num) | |
297 { | |
298 uint8_t resivebuf[2]; | |
299 | |
300 uint8_t cmd = CMD_PROM_RD+coef_num*2; | |
301 I2C_Master_Transmit( DEVICE_PRESSURE, &cmd, 1); | |
302 I2C_Master_Receive( DEVICE_PRESSURE, resivebuf, 2); | |
303 return (256*(uint16_t)resivebuf[0]) + (uint16_t)resivebuf[1]; | |
304 } | |
305 | |
306 | |
307 | |
308 uint8_t pressure_update(void) | |
309 { | |
310 HAL_StatusTypeDef statusReturn = HAL_TIMEOUT; | |
311 | |
312 statusReturn = pressure_sensor_get_data(); | |
313 pressure_calculation(); | |
314 return (uint8_t)statusReturn; | |
315 } | |
316 | |
317 | |
318 uint32_t pressure_sensor_get_one_value(uint8_t cmd, HAL_StatusTypeDef *statusReturn) | |
319 { | |
320 uint8_t command = CMD_ADC_CONV + cmd; | |
321 HAL_StatusTypeDef statusReturnTemp = HAL_TIMEOUT; | |
322 | |
323 statusReturnTemp = I2C_Master_Transmit( DEVICE_PRESSURE, &command, 1); | |
324 | |
325 if(statusReturn) | |
326 { | |
327 *statusReturn = statusReturnTemp; | |
328 } | |
329 | |
330 switch (cmd & 0x0f) // wait necessary conversion time | |
331 { | |
332 case CMD_ADC_256 : HAL_Delay(1); break; | |
333 case CMD_ADC_512 : HAL_Delay(3); break; | |
334 case CMD_ADC_1024: HAL_Delay(4); break; | |
335 case CMD_ADC_2048: HAL_Delay(6); break; | |
336 case CMD_ADC_4096: HAL_Delay(10); break; | |
337 } | |
338 return get_adc(); | |
339 } | |
340 | |
341 | |
342 HAL_StatusTypeDef pressure_sensor_get_data(void) | |
343 { | |
344 HAL_StatusTypeDef statusReturn1 = HAL_TIMEOUT; | |
345 HAL_StatusTypeDef statusReturn2 = HAL_TIMEOUT; | |
346 | |
347 D2 = pressure_sensor_get_one_value(CMD_ADC_D2 + CMD_ADC_4096, &statusReturn1); | |
348 D1 = pressure_sensor_get_one_value(CMD_ADC_D1 + CMD_ADC_4096, &statusReturn2); | |
349 | |
350 if(statusReturn2 > statusReturn1) // if anything is not HAL_OK (0x00) or worse | |
351 return statusReturn2; | |
352 else | |
353 return statusReturn1; | |
354 } | |
355 | |
356 | |
357 void pressure_sensor_get_pressure_raw(void) | |
358 { | |
359 D1 = pressure_sensor_get_one_value(CMD_ADC_D1 + CMD_ADC_4096, 0); | |
360 } | |
361 | |
362 | |
363 void pressure_sensor_get_temperature_raw(void) | |
364 { | |
365 D2 = pressure_sensor_get_one_value(CMD_ADC_D2 + CMD_ADC_4096, 0); | |
366 } | |
367 | |
368 | |
369 void pressure_calculation(void) | |
370 { | |
371 if(I2C1_Status() != HAL_OK) | |
372 return; | |
373 | |
374 pressure_calculation_AN520_004_mod_MS5803_30BA__09_2015(); | |
375 return; | |
376 | |
377 // before October 2016: pressure_calculation_old(); | |
378 | |
379 // pressure_calculation_new(); | |
380 } | |
381 | |
382 void pressure_calculation_AN520_004_mod_MS5803_30BA__09_2015(void) | |
383 { | |
384 uint32_t local_D1; // ADC value of the pressure conversion | |
385 uint32_t local_D2; // ADC value of the temperature conversion | |
386 int32_t local_Px10; // compensated pressure value | |
387 int32_t local_Tx100; // compensated temperature value | |
388 int64_t local_dT; // int32_t, difference between actual and measured temperature | |
389 int64_t local_OFF; // offset at actual temperature | |
390 int64_t local_SENS; // sensitivity at actual temperature | |
391 | |
392 int64_t T2; | |
393 int64_t OFF2; | |
394 int64_t SENS2; | |
395 | |
396 local_D1 = D1; | |
397 local_D2 = D2; | |
398 | |
399 local_dT = ((int64_t)local_D2) - ((int64_t)C[5]) * 256; //pow(2,8); | |
400 local_OFF = ((int64_t)C[2]) * 65536 + local_dT * ((int64_t)C[4]) / 128; // pow(2,16), pow(2,7) | |
401 local_SENS = ((int64_t)C[1]) * 32768 + local_dT * ((int64_t)C[3]) / 256; // pow(2,15), pow(2,8) | |
402 | |
403 local_Tx100 = (int32_t)(2000 + (local_dT * ((int64_t)C[6])) / 8388608);// pow(2,23) | |
404 | |
405 | |
406 if(local_Tx100 < 2000) // low temperature | |
407 { | |
408 T2 = 3 * local_dT; | |
409 T2 *= local_dT; | |
410 T2 /= 8589934592; | |
411 | |
412 OFF2 = ((int64_t)local_Tx100) - 2000; | |
413 OFF2 *= OFF2; | |
414 OFF2 *= 3; | |
415 OFF2 /= 2; | |
416 | |
417 SENS2 = ((int64_t)local_Tx100) - 2000; | |
418 SENS2 *= SENS2; | |
419 SENS2 *= 5; | |
420 SENS2 /= 8; | |
421 | |
422 local_Tx100 -= (int32_t)T2; | |
423 local_OFF -= OFF2; | |
424 local_SENS -= SENS2; | |
425 } | |
426 else | |
427 { | |
428 T2 = 7 * local_dT; | |
429 T2 *= local_dT; | |
430 T2 /= 137438953472; | |
431 | |
432 OFF2 = ((int64_t)local_Tx100) - 2000; | |
433 OFF2 *= OFF2; | |
434 OFF2 /= 16; | |
435 | |
436 local_Tx100 -= (int32_t)T2; | |
437 local_OFF -= OFF2; | |
438 } | |
439 | |
440 local_Px10 = (int32_t)( | |
441 (((int64_t)((local_D1 * local_SENS) / 2097152)) - local_OFF) | |
442 / 8192 );// )) / 10; // pow(2,21), pow(2,13) | |
443 | |
444 ambient_temperature = ((float)local_Tx100) / 100; | |
445 ambient_pressure_mbar = ((float)local_Px10) / 10; | |
446 } | |
447 | |
448 | |
449 void pressure_calculation_new(void) | |
450 { | |
451 #define POW2_8 (256) | |
452 #define POW2_17 (131072) | |
453 #define POW2_6 (64) | |
454 #define POW2_16 (65536) | |
455 #define POW2_7 (128) | |
456 #define POW2_23 (8388608) | |
457 #define POW2_21 (2097152) | |
458 #define POW2_15 (32768) | |
459 #define POW2_13 (8192) | |
460 #define POW2_37 (137438953472) | |
461 #define POW2_4 (16) | |
462 #define POW2_33 (8589934592) | |
463 #define POW2_3 (8) | |
464 | |
465 int32_t P; // compensated pressure value | |
466 int32_t T; // compensated temperature value | |
467 int32_t dT; // difference between actual and measured temperature | |
468 int64_t OFF; // offset at actual temperature | |
469 int64_t SENS; | |
470 | |
471 int32_t T2; | |
472 int64_t OFF2; | |
473 int64_t SENS2; | |
474 | |
475 dT = ((int32_t)D2) - ((int32_t)C[5]) * POW2_8; | |
476 OFF = ((int64_t)C[2]) * POW2_16 + ((int64_t)dT) * ((int64_t)C[4]) / POW2_7; | |
477 SENS = ((int64_t)C[1]) * POW2_15 + ((int64_t)dT) * ((int64_t)C[3]) / POW2_8; | |
478 | |
479 T = 2000 + (dT * ((int32_t)C[6])) / POW2_23; | |
480 | |
481 | |
482 if(T < 2000) // low temperature | |
483 { | |
484 T2 = 3 * dT * dT; | |
485 T2 /= POW2_33; | |
486 OFF2 = ((int64_t)T) - 2000; | |
487 OFF2 *= OFF2; | |
488 OFF2 *= 3; | |
489 OFF2 /= 2; | |
490 SENS2 = ((int64_t)T) - 2000; | |
491 SENS2 *= SENS2; | |
492 SENS2 *= 5; | |
493 SENS2 /= POW2_3; | |
494 } | |
495 else // high temperature | |
496 { | |
497 T2 = 7 * dT * dT; | |
498 T2 /= POW2_37; | |
499 OFF2 = ((int64_t)T) - 2000; | |
500 OFF2 *= OFF2; | |
501 OFF2 /= POW2_4; | |
502 SENS2 = 0; | |
503 } | |
504 | |
505 T = T - T2; | |
506 OFF = OFF - OFF2; | |
507 SENS = SENS - SENS2; | |
508 | |
509 P = (int32_t)(((((int64_t)D1) * SENS) / POW2_21 - OFF) / POW2_13); | |
510 | |
511 ambient_temperature = ((float)T) / 100; | |
512 ambient_pressure_mbar = ((float)P) / 10; | |
513 } | |
514 | |
515 | |
516 void pressure_calculation_old(void) { | |
517 // | |
518 double ambient_temperature_centigrad = 0; | |
519 double ambient_pressure_decimbar = 0; | |
520 | |
521 // static for debug | |
522 static int64_t dt = 0; | |
523 static int64_t temp = 0; | |
524 static int64_t ms_off = 0; | |
525 static int64_t sens = 0; | |
526 // | |
527 static int64_t ms_off2 = 0; | |
528 static int64_t sens2 = 0; | |
529 static int64_t t2 = 0; | |
530 | |
531 /* info | |
532 uint16_t C[8] = { 1 }; | |
533 uint32_t D1 = 1; | |
534 uint32_t D2 = 1; | |
535 uint8_t n_crc; | |
536 */ | |
537 if((D2 == 0) || (D1 == 0)) | |
538 return; | |
539 // | |
540 | |
541 // dT = D2 - C[5] * POW2_8; | |
542 // T = 2000 + (dT * C[6]) / POW2_23; | |
543 dt = (int64_t)D2 - C5_x_2p8; | |
544 //temp ; // in 10 milliGrad Celcius | |
545 ambient_temperature_centigrad = 2000 + dt * C[6] / 8388608; | |
546 | |
547 | |
548 if(ambient_temperature_centigrad < 2000) // low temperature | |
549 { | |
550 t2 = 3 * dt; | |
551 t2 *= dt; | |
552 t2 /= 8589934592; | |
553 ms_off2 = ambient_temperature_centigrad - 2000; | |
554 ms_off2 *= ms_off2; | |
555 sens2 = ms_off2; | |
556 ms_off2 *= 3; | |
557 ms_off2 /= 2; | |
558 sens2 *= 5; | |
559 sens2 /= 8; | |
560 } | |
561 else // high temperature | |
562 { | |
563 t2 = 7 * dt; | |
564 t2 *= dt; | |
565 t2 /= 137438953472; | |
566 ms_off2 = ambient_temperature_centigrad - 2000; | |
567 ms_off2 *= ms_off2; | |
568 ms_off2 /= 16; | |
569 sens2 = 0; | |
570 } | |
571 | |
572 | |
573 // | |
574 | |
575 // pressure | |
576 // OFF = C[2] * POW2_16 + dT * C[4] / POW2_7; | |
577 // SENS = C[1] * POW2_15 + dT * C[3] / POW2_8; | |
578 ms_off = C[4] * dt; | |
579 ms_off /= 128; | |
580 ms_off += C2_x_2p16; | |
581 // | |
582 sens = C[3] * dt; | |
583 sens /= 256; | |
584 sens += C1_x_2p15; | |
585 | |
586 // 2nd order correction | |
587 ambient_temperature_centigrad -= t2; | |
588 ms_off -= ms_off2; | |
589 sens -= sens2; | |
590 | |
591 ambient_temperature = ambient_temperature_centigrad / 100; | |
592 // P = (D1 * SENS / POW2_21 - OFF) / POW2_13; | |
593 temp = D1 * sens; | |
594 temp /= 2097152; | |
595 temp -= ms_off; | |
596 temp /= 8192; | |
597 ambient_pressure_decimbar = temp; // to float/double | |
598 ambient_pressure_mbar = ambient_pressure_decimbar / 10; | |
599 } | |
600 | |
601 | |
602 /* taken from AN520 by meas-spec.com dated 9. Aug. 2011 | |
603 * short and int are both 16bit according to AVR/GCC google results | |
604 */ | |
605 uint8_t crc4(uint16_t n_prom[]) | |
606 { | |
607 uint16_t cnt; // simple counter | |
608 uint16_t n_rem; // crc reminder | |
609 uint16_t crc_read; // original value of the crc | |
610 uint8_t n_bit; | |
611 n_rem = 0x00; | |
612 crc_read=n_prom[7]; //save read CRC | |
613 n_prom[7]=(0xFF00 & (n_prom[7])); //CRC byte is replaced by 0 | |
614 for (cnt = 0; cnt < 16; cnt++) // operation is performed on bytes | |
615 { // choose LSB or MSB | |
616 if (cnt%2==1) n_rem ^= (uint16_t) ((n_prom[cnt>>1]) & 0x00FF); | |
617 else n_rem ^= (uint16_t) (n_prom[cnt>>1]>>8); | |
618 for (n_bit = 8; n_bit > 0; n_bit--) | |
619 { | |
620 if (n_rem & (0x8000)) | |
621 { | |
622 n_rem = (n_rem << 1) ^ 0x3000; | |
623 } | |
624 else | |
625 { | |
626 n_rem = (n_rem << 1); | |
627 } | |
628 } | |
629 } | |
630 n_rem= (0x000F & (n_rem >> 12)); // // final 4-bit reminder is CRC code | |
631 n_prom[7]=crc_read; // restore the crc_read to its original place | |
632 return (n_rem ^ 0x00); | |
633 } | |
634 /* | |
635 void test_calculation(void) | |
636 { | |
637 C1 = 29112; | |
638 C2 = 26814; | |
639 C3 = 19125; | |
640 C4 = 17865; | |
641 C5 = 32057; | |
642 C6 = 31305; | |
643 | |
644 C2_x_2p16 = C2 * 65536; | |
645 C1_x_2p15 = C1 * 32768; | |
646 | |
647 D1 = 4944364; | |
648 D2 = 8198974; | |
649 pressure_calculation() ; | |
650 }; | |
651 */ | |
652 |