41 lines
1.1 KiB
C
41 lines
1.1 KiB
C
#ifndef AHT20_H
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#define AHT20_H
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#include <stdint.h>
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#define AHT20_ADDR 0x38 // AHT default i2c address
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#define AHT20_CMD_CALIBRATE 0xBE // Calibration command
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#define AHT20_CMD_TRIGGER 0xAC // Trigger reading command
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#define AHT20_CMD_SOFTRESET 0xBA // Soft reset command
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#define AHT20_CMD_STATUS 0x71
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#define AHT20_STATUS_BUSY 0x80 // Status bit for busy
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#define AHT20_STATUS_CALIBRATED 0x08 // Status bit for calibrated
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#define AHT20_OK 0x00
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#define AHT20_ERR_INIT 0x01 // Initialization or Calibration failed
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#define AHT20_ERR_BUSY 0x02 // Sensor measurement timeout
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#define AHT20_ERR_CRC 0x03 // Data corruption detected
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#define AHT20_ERR_I2C 0x04 // Generic I2C Bus error (NACK)
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#define STATUS_BUSY_BIT (1 << 7)
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#define STATUS_CAL_BIT (1 << 3)
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typedef struct {
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uint32_t hum_p_x100; // %RH * 100
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int32_t temp_c_x100; // DegC * 100
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} aht20_data;
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/**
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* Init sensor
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* Checks status 0x71 and performs calibration (0xBE) if required
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*/
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uint8_t aht20_init(void);
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/**
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* Trigger measurement, wait >80ms, poll busy bit, and read data
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* Checks CRC8
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*/
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uint8_t aht20_read(aht20_data* out_data);
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#endif // AHT20_H
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