LibDriver DHT11  2.0.0
DHT11 full-featured driver
driver_dht11.c
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1 
38 #include "driver_dht11.h"
39 
43 #define CHIP_NAME "ASAIR DHT11"
44 #define MANUFACTURER_NAME "ASAIR"
45 #define SUPPLY_VOLTAGE_MIN 3.3f
46 #define SUPPLY_VOLTAGE_MAX 5.5f
47 #define MAX_CURRENT 1.0f
48 #define TEMPERATURE_MIN -20.0f
49 #define TEMPERATURE_MAX 60.0f
50 #define DRIVER_VERSION 2000
60 static uint8_t a_dht11_reset(dht11_handle_t *handle)
61 {
62  uint8_t retry = 0;
63  uint8_t res;
64  uint8_t value;
65 
66  res = handle->bus_write(0); /* set low */
67  if (res != 0) /* check result */
68  {
69  handle->debug_print("dht11: bus write 0 failed.\n"); /* write failed */
70 
71  return 1; /* return error */
72  }
73  handle->delay_ms(20); /* wait 20ms */
74  handle->disable_irq(); /* disable interrupt */
75  res = handle->bus_write(1); /* set high */
76  if (res != 0) /* check result */
77  {
78  handle->enable_irq(); /* enable interrupt */
79  handle->debug_print("dht11: bus write 1 failed.\n"); /* write failed */
80 
81  return 1; /* return error */
82  }
83  handle->delay_us(30); /* wait 20-40us */
84  res = handle->bus_read((uint8_t *)&value); /* read 1 bit */
85  if (res != 0) /* check result */
86  {
87  handle->enable_irq(); /* enable interrupt */
88  handle->debug_print("dht11: bus read failed.\n"); /* read failed */
89 
90  return 1; /* return error */
91  }
92  while ((value != 0) && (retry < 100)) /* wait 40-80us */
93  {
94  res = handle->bus_read((uint8_t *)&value); /* read 1 bit */
95  if (res != 0) /* check result */
96  {
97  handle->enable_irq(); /* enable interrupt */
98  handle->debug_print("dht11: bus read failed.\n"); /* read failed */
99 
100  return 1; /* return error */
101  }
102  retry++; /* retry times++ */
103  handle->delay_us(1); /* delay 1us */
104  }
105  if (retry >= 100) /* if retry times is over 100 times */
106  {
107  handle->enable_irq(); /* enable interrupt */
108  handle->debug_print("dht11: bus no response.\n"); /* no response */
109 
110  return 1; /* return error */
111  }
112  else
113  {
114  retry = 0; /* reset retry times */
115  }
116  res = handle->bus_read((uint8_t *)&value); /* read 1 bit */
117  if (res != 0) /* check result */
118  {
119  handle->enable_irq(); /* enable interrupt */
120  handle->debug_print("dht11: bus read failed.\n"); /* read failed */
121 
122  return 1; /* return error */
123  }
124  while ((!value) && (retry < 100)) /* wait for 40-80us */
125  {
126  res = handle->bus_read((uint8_t *)&value); /* read 1 bit */
127  if (res != 0) /* check result */
128  {
129  handle->enable_irq(); /* enable interrupt */
130  handle->debug_print("dht11: bus read failed.\n"); /* read failed */
131 
132  return 1; /* return error */
133  }
134  retry++; /* retry times++ */
135  handle->delay_us(1); /* delay 1 us */
136  }
137  if (retry >= 100) /* if retry times is over 100 times */
138  {
139  handle->enable_irq(); /* enable interrupt */
140  handle->debug_print("dht11: bus no response.\n"); /* no response */
141 
142  return 1; /* return error */
143  }
144  handle->enable_irq(); /* enable interrupt */
145 
146  return 0; /* success return 0 */
147 }
148 
158 static uint8_t a_dht11_read_bit(dht11_handle_t *handle, uint8_t *value)
159 {
160  uint8_t retry = 0;
161  uint8_t res;
162 
163  res = handle->bus_read((uint8_t *)value); /* read 1 bit */
164  if (res != 0) /* check result */
165  {
166  handle->debug_print("dht11: bus read failed.\n"); /* read failed */
167 
168  return 1; /* return error */
169  }
170  while (((*value) != 0) && (retry < 100)) /* wait 100us */
171  {
172  res = handle->bus_read((uint8_t *)value); /* read 1 bit */
173  if (res != 0) /* check result */
174  {
175  handle->debug_print("dht11: bus read failed.\n"); /* read failed */
176 
177  return 1; /* return error */
178  }
179  retry++; /* retry times++ */
180  handle->delay_us(1); /* delay 1 us */
181  }
182  retry = 0; /* reset retry times */
183  res = handle->bus_read((uint8_t *)value); /* read 1 bit */
184  if (res != 0) /* check result */
185  {
186  handle->debug_print("dht11: bus read failed.\n"); /* read failed */
187 
188  return 1; /* return error */
189  }
190  while ((!(*value)) && (retry < 100)) /* wait 100us */
191  {
192  res = handle->bus_read((uint8_t *)value); /* read 1 bit */
193  if (res != 0) /* check result */
194  {
195  handle->debug_print("dht11: bus read failed.\n"); /* read failed */
196 
197  return 1; /* return error */
198  }
199  retry++; /* retry times++ */
200  handle->delay_us(1); /* wait 1 us */
201  }
202  handle->delay_us(40); /* wait 40us */
203  res = handle->bus_read((uint8_t *)value); /* read 1 bit */
204  if (res != 0) /* check result */
205  {
206  handle->debug_print("dht11: bus read failed.\n"); /* read failed */
207 
208  return 1; /* return error */
209  }
210  else
211  {
212  return 0; /* success return 0 */
213  }
214 }
215 
225 static uint8_t a_dht11_read_byte(dht11_handle_t *handle, uint8_t *byte)
226 {
227  uint8_t i;
228  uint8_t res;
229  uint8_t value;
230 
231  *byte = 0; /* set byte 0 */
232  for (i = 0; i < 8; i++) /* read 8 bits */
233  {
234  *byte <<= 1; /* left shift 1 bit */
235  res = a_dht11_read_bit(handle, (uint8_t *)&value); /* read 1 bit */
236  if (res != 0) /* check result */
237  {
238  handle->debug_print("dht11: bus read failed.\n"); /* read failed */
239 
240  return 1; /* return error */
241  }
242  *byte |= value; /* set LSB */
243  }
244 
245  return 0; /* success return 0 */
246 }
247 
260 uint8_t dht11_read_humidity(dht11_handle_t *handle, uint16_t *raw, uint8_t *s)
261 {
262  uint8_t buf[5];
263  uint8_t i;
264 
265  if (handle == NULL) /* check handle */
266  {
267  return 2; /* return error */
268  }
269  if (handle->inited != 1) /* check handle initialization */
270  {
271  return 3; /* return error */
272  }
273 
274  if (a_dht11_reset(handle) == 0) /* reset the chip */
275  {
276  handle->disable_irq(); /* disable interrupt */
277  for (i = 0; i < 5; i++) /* read 5 bytes */
278  {
279  if (a_dht11_read_byte(handle, (uint8_t *)&buf[i]) != 0) /* read each byte */
280  {
281  handle->enable_irq(); /* enable interrupt */
282  handle->debug_print("dht11: read byte failed.\n"); /* read failed */
283 
284  return 1; /* return error */
285  }
286  }
287  handle->enable_irq(); /* enable interrupt */
288  if ((buf[0] + buf[1] + buf[2] + buf[3]) == buf[4]) /* calculate checksum */
289  {
290  *raw = (uint16_t)buf[0] << 8 | buf[1]; /* get raw data */
291  *s = buf[0]; /* convert raw data to real data */
292 
293  return 0; /* success return 0 */
294  }
295  else
296  {
297  handle->debug_print("dht11: data check failed.\n"); /* checksum error */
298 
299  return 1; /* return error */
300  }
301  }
302  else
303  {
304  handle->debug_print("dht11: reset failed.\n"); /* reset failed */
305 
306  return 1; /* return error */
307  }
308 }
309 
324 uint8_t dht11_read_temperature_humidity(dht11_handle_t *handle, uint16_t *temperature_raw, float *temperature_s,
325  uint16_t *humidity_raw, uint8_t *humidity_s)
326 {
327  uint8_t buf[5];
328  uint8_t i;
329 
330  if (handle == NULL) /* check handle */
331  {
332  return 2; /* return error */
333  }
334  if (handle->inited != 1) /* check handle initialization */
335  {
336  return 3; /* return error */
337  }
338 
339  if (a_dht11_reset(handle) == 0) /* reset the chip */
340  {
341  handle->disable_irq(); /* disable interrupt */
342  for (i = 0; i < 5; i++) /* read 5 bytes */
343  {
344  if (a_dht11_read_byte(handle, (uint8_t *)&buf[i]) != 0) /* read each byte */
345  {
346  handle->enable_irq(); /* enable interrupt */
347  handle->debug_print("dht11: read byte failed.\n"); /* read failed */
348 
349  return 1; /* return error */
350  }
351  }
352  handle->enable_irq(); /* enable interrupt */
353  if ((buf[0] + buf[1] + buf[2] + buf[3]) == buf[4]) /* calculate checksum */
354  {
355  if (buf[3] > 127) /* if temperature is below zero */
356  {
357  *temperature_raw = (uint16_t)buf[2] << 8 | buf[3]; /* get temperature raw data */
358  *temperature_s= (float)(-(buf[2] * 10 +
359  (buf[3] & ~(1<<7)))) / 10.0f; /* convert temperature raw data to temperature real data */
360  }
361  else
362  {
363  *temperature_raw = (uint16_t)buf[2] << 8 | buf[3]; /* get temperature raw data */
364  *temperature_s= (float)(buf[2]*10 + buf[3]) / 10.0f; /* convert temperature raw data to temperature real data */
365  }
366  *humidity_raw = (uint16_t)buf[0] << 8 | buf[1]; /* get humidity raw */
367  *humidity_s = buf[0]; /* convert humidity raw data to real data */
368 
369  return 0; /* success return 0 */
370  }
371  else
372  {
373  handle->debug_print("dht11: data check failed.\n"); /* checksum error */
374 
375  return 1; /* return error */
376  }
377  }
378  else
379  {
380  handle->debug_print("dht11: reset failed.\n"); /* reset failed */
381 
382  return 1; /* return error */
383  }
384 }
385 
398 uint8_t dht11_read_temperature(dht11_handle_t *handle, uint16_t *raw, float *s)
399 {
400  uint8_t buf[5];
401  uint8_t i;
402 
403  if (handle == NULL) /* check handle */
404  {
405  return 2; /* return error */
406  }
407  if (handle->inited != 1) /* check handle initialization */
408  {
409  return 3; /* return error */
410  }
411 
412  if (a_dht11_reset(handle) == 0) /* reset the chip */
413  {
414  handle->disable_irq(); /* disable interrupt */
415  for (i = 0; i < 5; i++) /* read 5 bytes */
416  {
417  if (a_dht11_read_byte(handle, (uint8_t *)&buf[i]) != 0) /* read each byte */
418  {
419  handle->enable_irq(); /* enable interrupt */
420  handle->debug_print("dht11: read byte failed.\n"); /* read failed */
421 
422  return 1; /* return error */
423  }
424  }
425  handle->enable_irq(); /* enable interrupt */
426  if ((buf[0] + buf[1] + buf[2] + buf[3]) == buf[4]) /* calculate checksum */
427  {
428  if (buf[3] > 127) /* if temperature is below zero */
429  {
430  *raw = (uint16_t)buf[2] << 8 | buf[3]; /* get temperature raw data */
431  *s= (float)(-(buf[2] * 10 + (buf[3] & ~(1<<7)))) / 10.0f; /* convert temperature raw data to temperature real data */
432  }
433  else
434  {
435  *raw = (uint16_t)buf[2] << 8 | buf[3]; /* get temperature raw data */
436  *s= (float)(buf[2] * 10 + buf[3]) / 10.0f; /* convert temperature raw data to temperature real data */
437  }
438 
439  return 0; /* success return 0 */
440  }
441  else
442  {
443  handle->debug_print("dht11: data check failed.\n"); /* checksum error */
444 
445  return 1; /* return error */
446  }
447  }
448  else
449  {
450  handle->debug_print("dht11: reset failed.\n"); /* reset failed */
451 
452  return 1; /* return error */
453  }
454 }
455 
467 uint8_t dht11_init(dht11_handle_t *handle)
468 {
469  if (handle == NULL) /* check handle */
470  {
471  return 2; /* return error */
472  }
473  if (handle->debug_print == NULL) /* check debug_print */
474  {
475  return 3; /* return error */
476  }
477  if (handle->bus_init == NULL) /* check bus_init */
478  {
479  handle->debug_print("dht11: bus_init is null.\n"); /* bus_init is null */
480 
481  return 3; /* return error */
482  }
483  if (handle->bus_deinit == NULL) /* check bus_deinit */
484  {
485  handle->debug_print("dht11: bus_deinit is null.\n"); /* bus_deinit is null */
486 
487  return 3; /* return error */
488  }
489  if (handle->bus_read == NULL) /* check bus_read */
490  {
491  handle->debug_print("dht11: bus_read is null.\n"); /* bus_read is null */
492 
493  return 3; /* return error */
494  }
495  if (handle->bus_write == NULL) /* check bus_write */
496  {
497  handle->debug_print("dht11: bus_write is null.\n"); /* bus_write is null */
498 
499  return 3; /* return error */
500  }
501  if (handle->delay_ms == NULL) /* check delay_ms */
502  {
503  handle->debug_print("dht11: delay_ms is null.\n"); /* delay_ms is null */
504 
505  return 3; /* return error */
506  }
507  if (handle->delay_us == NULL) /* check delay_us */
508  {
509  handle->debug_print("dht11: delay_us is null.\n"); /* delay_us is null */
510 
511  return 3; /* return error */
512  }
513  if (handle->enable_irq == NULL) /* check enable_irq */
514  {
515  handle->debug_print("dht11: enable_irq is null.\n"); /* enable_irq is null */
516 
517  return 3; /* return error */
518  }
519  if (handle->disable_irq == NULL) /* check disable_irq */
520  {
521  handle->debug_print("dht11: disable_irq is null.\n"); /* disable_irq is null */
522 
523  return 3; /* return error */
524  }
525 
526  if (handle->bus_init() != 0) /* initialize bus */
527  {
528  handle->debug_print("dht11: bus init failed.\n"); /* bus init failed */
529 
530  return 1; /* return error */
531  }
532  if (a_dht11_reset(handle) != 0) /* reset the chip */
533  {
534  handle->debug_print("dht11: reset failed.\n"); /* reset failed */
535  (void)handle->bus_deinit(); /* close bus */
536 
537  return 4; /* return error */
538  }
539  handle->inited = 1; /* flag finish initialization */
540 
541  return 0; /* success return 0 */
542 }
543 
554 uint8_t dht11_deinit(dht11_handle_t *handle)
555 {
556  if (handle == NULL) /* check handle */
557  {
558  return 2; /* return error */
559  }
560  if (handle->inited != 1) /* check handle initialization */
561  {
562  return 3; /* return error */
563  }
564 
565  if (handle->bus_deinit() != 0) /* close bus */
566  {
567  handle->debug_print("dht11: deinit failed.\n"); /* deinit failed */
568 
569  return 1; /* return error */
570  }
571  handle->inited = 0; /* flag close */
572 
573  return 0; /* success return 0 */
574 }
575 
584 uint8_t dht11_info(dht11_info_t *info)
585 {
586  if (info == NULL) /* check handle */
587  {
588  return 2; /* return error */
589  }
590 
591  memset(info, 0, sizeof(dht11_info_t)); /* initialize dht11 info structure */
592  strncpy(info->chip_name, CHIP_NAME, 32); /* copy chip name */
593  strncpy(info->manufacturer_name, MANUFACTURER_NAME, 32); /* copy manufacturer name */
594  strncpy(info->interface, "GPIO", 8); /* copy interface name */
595  info->supply_voltage_min_v = SUPPLY_VOLTAGE_MIN; /* set minimal supply voltage */
596  info->supply_voltage_max_v = SUPPLY_VOLTAGE_MAX; /* set maximum supply voltage */
597  info->max_current_ma = MAX_CURRENT; /* set maximum current */
598  info->temperature_max = TEMPERATURE_MAX; /* set minimal temperature */
599  info->temperature_min = TEMPERATURE_MIN; /* set maximum temperature */
600  info->driver_version = DRIVER_VERSION; /* set driver version */
601 
602  return 0; /* success return 0 */
603 }
MAX_CURRENT
#define MAX_CURRENT
Definition: driver_dht11.c:47
SUPPLY_VOLTAGE_MAX
#define SUPPLY_VOLTAGE_MAX
Definition: driver_dht11.c:46
TEMPERATURE_MAX
#define TEMPERATURE_MAX
Definition: driver_dht11.c:49
MANUFACTURER_NAME
#define MANUFACTURER_NAME
Definition: driver_dht11.c:44
TEMPERATURE_MIN
#define TEMPERATURE_MIN
Definition: driver_dht11.c:48
SUPPLY_VOLTAGE_MIN
#define SUPPLY_VOLTAGE_MIN
Definition: driver_dht11.c:45
CHIP_NAME
#define CHIP_NAME
chip information definition
Definition: driver_dht11.c:43
DRIVER_VERSION
#define DRIVER_VERSION
Definition: driver_dht11.c:50
driver_dht11.h
driver dht11 header file
dht11_read_temperature_humidity
uint8_t dht11_read_temperature_humidity(dht11_handle_t *handle, uint16_t *temperature_raw, float *temperature_s, uint16_t *humidity_raw, uint8_t *humidity_s)
read the temperature and humidity data
Definition: driver_dht11.c:324
dht11_info
uint8_t dht11_info(dht11_info_t *info)
get chip's information
Definition: driver_dht11.c:584
dht11_init
uint8_t dht11_init(dht11_handle_t *handle)
initialize the chip
Definition: driver_dht11.c:467
dht11_read_humidity
uint8_t dht11_read_humidity(dht11_handle_t *handle, uint16_t *raw, uint8_t *s)
read the humidity data
Definition: driver_dht11.c:260
dht11_deinit
uint8_t dht11_deinit(dht11_handle_t *handle)
close the chip
Definition: driver_dht11.c:554
dht11_read_temperature
uint8_t dht11_read_temperature(dht11_handle_t *handle, uint16_t *raw, float *s)
read the temperature data
Definition: driver_dht11.c:398
dht11_handle_s
dht11 handle structure definition
Definition: driver_dht11.h:64
dht11_handle_s::enable_irq
void(* enable_irq)(void)
Definition: driver_dht11.h:71
dht11_handle_s::inited
uint8_t inited
Definition: driver_dht11.h:74
dht11_handle_s::bus_deinit
uint8_t(* bus_deinit)(void)
Definition: driver_dht11.h:68
dht11_handle_s::delay_ms
void(* delay_ms)(uint32_t ms)
Definition: driver_dht11.h:69
dht11_handle_s::debug_print
void(* debug_print)(const char *const fmt,...)
Definition: driver_dht11.h:73
dht11_handle_s::delay_us
void(* delay_us)(uint32_t us)
Definition: driver_dht11.h:70
dht11_handle_s::disable_irq
void(* disable_irq)(void)
Definition: driver_dht11.h:72
dht11_handle_s::bus_read
uint8_t(* bus_read)(uint8_t *value)
Definition: driver_dht11.h:66
dht11_handle_s::bus_write
uint8_t(* bus_write)(uint8_t value)
Definition: driver_dht11.h:67
dht11_handle_s::bus_init
uint8_t(* bus_init)(void)
Definition: driver_dht11.h:65
dht11_info_s
dht11 info structure definition
Definition: driver_dht11.h:81
dht11_info_s::temperature_max
float temperature_max
Definition: driver_dht11.h:89
dht11_info_s::supply_voltage_max_v
float supply_voltage_max_v
Definition: driver_dht11.h:86
dht11_info_s::driver_version
uint32_t driver_version
Definition: driver_dht11.h:90
dht11_info_s::temperature_min
float temperature_min
Definition: driver_dht11.h:88
dht11_info_s::max_current_ma
float max_current_ma
Definition: driver_dht11.h:87
dht11_info_s::manufacturer_name
char manufacturer_name[32]
Definition: driver_dht11.h:83
dht11_info_s::supply_voltage_min_v
float supply_voltage_min_v
Definition: driver_dht11.h:85
dht11_info_s::interface
char interface[8]
Definition: driver_dht11.h:84
dht11_info_s::chip_name
char chip_name[32]
Definition: driver_dht11.h:82