43 lines
1.1 KiB
C
43 lines
1.1 KiB
C
#include "dht22.h"
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#include "sdkconfig.h"
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#define DATA_GPIO CONFIG_DHT22_DATA_GPIO
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#if DATA_GPIO == -1
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#error "Please define your DHT22 GPIO Data Pin"
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#endif /* CONFIG_DHT22_DATA_GPIO == -1 */
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static const char* TAG = "DHT22";
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deci_percent _dht22_relative_humidity = UINT16_MAX;
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deci_degrees_c _dht22_temperature = INT16_MIN;
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dht22_error dht22_read() {
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uint8_t data[5] = {0};
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// TODO: Actually figure out how to read the data from the chip.
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// TODO test that data[x] << 8 will be promoted to 16bits otherwise I'm shifting them to just zeros
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_dht22_relative_humidity = data[0] << 8 | data[1];
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_dht22_temperature = (data[2] & 0x7f) << 8 | data[3];
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if (data[2] & 0x80) {
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_dht22_temperature = -1 * _dht22_temperature;
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}
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uint8_t checksum_val = (data[0] + data[1] + data[2] + data[2]) & 0xff;
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if (checksum_val != data[5]) {
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_dht22_relative_humidity = UINT16_MAX;
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_dht22_temperature = INT16_MIN;
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return DHT22_CHECKSUM_ERROR;
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}
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return DHT22_OK;
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}
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deci_percent dht22_relative_humidity() {
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return _dht22_relative_humidity;
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}
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deci_degrees_c dht22_temperature() {
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return _dht22_temperature;
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}
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