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【CANNON试用体验】传感器——HTS221温湿度计

dvd1478

2016-1-29 11:44:03 7030

HTS221温湿度计.pdf (822.78 KB, 下载次数: 14 )

一、HTS221的参数

二、数据通信接口

标准的I2C/SPI接口

注意以下几个寄存器即可

三、数据计算

HTS221 采用了线性插值法进行校准，其原理如下：

其算法如下：

/**

* @brief HTS221 Calibration procedure

* @retval HUM_TEMP_OK in case of success, an error code otherwise

static HUM_TEMP_StatusTypeDef HTS221_Calibration(void)

{

/* Temperature Calibration */

/* Temperature in degree for calibration ( "/8" to obtain float) */

uint16_t T0_degC_x8_L, T0_degC_x8_H, T1_degC_x8_L, T1_degC_x8_H;

uint8_t H0_rh_x2, H1_rh_x2;

uint8_t tempReg[2] = {0, 0};

if(HTS221_IO_Read(tempReg, HTS221_ADDRESS, HTS221_T0_degC_X8_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

T0_degC_x8_L = (uint16_t)tempReg[0];

if(HTS221_IO_Read(tempReg, HTS221_ADDRESS, HTS221_T1_T0_MSB_X8_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

T0_degC_x8_H = (uint16_t) (tempReg[0] & 0x03);

T0_degC = ((float)((T0_degC_x8_H << 8) | (T0_degC_x8_L))) / 8;

if(HTS221_IO_Read(tempReg, HTS221_ADDRESS, HTS221_T1_degC_X8_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

T1_degC_x8_L = (uint16_t)tempReg[0];

if(HTS221_IO_Read(tempReg, HTS221_ADDRESS, HTS221_T1_T0_MSB_X8_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

T1_degC_x8_H = (uint16_t) (tempReg[0] & 0x0C);

T1_degC_x8_H = T1_degC_x8_H >> 2;

T1_degC = ((float)((T1_degC_x8_H << 8) | (T1_degC_x8_L))) / 8;

if(HTS221_IO_Read(tempReg, HTS221_ADDRESS, (HTS221_T0_OUT_L_ADDR | HTS221_I2C_MULTIPLEBYTE_CMD), 2) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

T0_out = ((((int16_t)tempReg[1]) << 8) + (int16_t)tempReg[0]);

if(HTS221_IO_Read(tempReg, HTS221_ADDRESS, (HTS221_T1_OUT_L_ADDR | HTS221_I2C_MULTIPLEBYTE_CMD), 2) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

T1_out = ((((int16_t)tempReg[1]) << 8) + (int16_t)tempReg[0]);

/* Humidity Calibration */

/* Humidity in degree for calibration ( "/2" to obtain float) */

if(HTS221_IO_Read(&H0_rh_x2, HTS221_ADDRESS, HTS221_H0_RH_X2_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

if(HTS221_IO_Read(&H1_rh_x2, HTS221_ADDRESS, HTS221_H1_RH_X2_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

if(HTS221_IO_Read(&tempReg[0], HTS221_ADDRESS, (HTS221_H0_T0_OUT_L_ADDR | HTS221_I2C_MULTIPLEBYTE_CMD),

2) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

H0_T0_out = ((((int16_t)tempReg[1]) << 8) + (int16_t)tempReg[0]);

if(HTS221_IO_Read(&tempReg[0], HTS221_ADDRESS, (HTS221_H1_T0_OUT_L_ADDR | HTS221_I2C_MULTIPLEBYTE_CMD),

2) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

H1_T0_out = ((((int16_t)tempReg[1]) << 8) + (int16_t)tempReg[0]);

H0_rh = ((float)H0_rh_x2) / 2;

H1_rh = ((float)H1_rh_x2) / 2;

return HUM_TEMP_OK;

}

/**

* @brief Read HTS221 output register, and calculate the humidity

* @param pfData the pointer to data output

* @retval HUM_TEMP_OK in case of success, an error code otherwise

static HUM_TEMP_StatusTypeDef HTS221_GetHumidity(float* pfData)

{

int16_t H_T_out, humidity_t;

uint8_t tempReg[2] = {0, 0};

uint8_t tmp = 0x00;

float H_rh;

if(HTS221_IO_Read(&tmp, HTS221_ADDRESS, HTS221_CTRL_REG1_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

/* Output Data Rate selection */

tmp &= (HTS221_ODR_MASK);

if(tmp == 0x00)

{

if(HTS221_IO_Read(&tmp, HTS221_ADDRESS, HTS221_CTRL_REG2_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

/* Serial Interface Mode selection */

tmp &= ~(HTS221_ONE_SHOT_MASK);

tmp |= HTS221_ONE_SHOT_START;

if(HTS221_IO_Write(&tmp, HTS221_ADDRESS, HTS221_CTRL_REG2_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

{

if(HTS221_IO_Read(&tmp, HTS221_ADDRESS, HTS221_STATUS_REG_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

while(!(tmp && 0x02));

}

if(HTS221_IO_Read(&tempReg[0], HTS221_ADDRESS, (HTS221_HUMIDITY_OUT_L_ADDR | HTS221_I2C_MULTIPLEBYTE_CMD),

2) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

H_T_out = ((((int16_t)tempReg[1]) << 8) + (int16_t)tempReg[0]);

H_rh = ( float )(((( H_T_out - H0_T0_out ) * ( H1_rh - H0_rh )) / ( H1_T0_out - H0_T0_out )) + H0_rh );

// Truncate to specific number of decimal digits 先乘后除为的是保留有效的小数值可理解为四舍五入

humidity_t = (uint16_t)(H_rh * pow(10, HUM_DECIMAL_DIGITS)); /* 10^HUM_DECIMAL_DIGITS */

*pfData = ((float)humidity_t) / pow(10, HUM_DECIMAL_DIGITS);

// Prevent data going below 0% and above 100% due to linear interpolation

if ( *pfData < 0.0f ) *pfData = 0.0f;

if ( *pfData > 100.0f ) *pfData = 100.0f;

return HUM_TEMP_OK;

}

/**

* @brief Read HTS221 output register, and calculate the temperature

* @param pfData the pointer to data output

* @retval HUM_TEMP_OK in case of success, an error code otherwise

static HUM_TEMP_StatusTypeDef HTS221_GetTemperature(float* pfData)

{

int16_t T_out, temperature_t;

uint8_t tempReg[2] = {0, 0};

uint8_t tmp = 0x00;

float T_degC;

if(HTS221_IO_Read(&tmp, HTS221_ADDRESS, HTS221_CTRL_REG1_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

/* Output Data Rate selection */

tmp &= (HTS221_ODR_MASK);

if(tmp == 0x00)

{

if(HTS221_IO_Read(&tmp, HTS221_ADDRESS, HTS221_CTRL_REG2_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

/* Serial Interface Mode selection */

tmp &= ~(HTS221_ONE_SHOT_MASK);

tmp |= HTS221_ONE_SHOT_START;

if(HTS221_IO_Write(&tmp, HTS221_ADDRESS, HTS221_CTRL_REG2_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

{

if(HTS221_IO_Read(&tmp, HTS221_ADDRESS, HTS221_STATUS_REG_ADDR, 1) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

while(!(tmp && 0x01)); /* 等待数据转换结束 */

}

if(HTS221_IO_Read(&tempReg[0], HTS221_ADDRESS, (HTS221_TEMP_OUT_L_ADDR | HTS221_I2C_MULTIPLEBYTE_CMD),

2) != HUM_TEMP_OK)

{

return HUM_TEMP_ERROR;

}

T_out = ((((int16_t)tempReg[1]) << 8) + (int16_t)tempReg[0]);

T_degC = ((float)(T_out - T0_out)) / (T1_out - T0_out) * (T1_degC - T0_degC) + T0_degC;

temperature_t = (int16_t)(T_degC * pow(10, TEMP_DECIMAL_DIGITS));

*pfData = ((float)temperature_t) / pow(10, TEMP_DECIMAL_DIGITS);

return HUM_TEMP_OK;

}

在cannon对于 HTS221 是这样读取的
juma_sensor.c->static void read_temp_hum(void* args)
调用x_nucleo_iks01a1074_hum_temp.c 对HTS221进行封装的BSP_HUM_TEMP的操作
实际上是调用 hts221.c
这样做的目的为了封装温度传感器这系列的产品，进行类的操作

/**

* @brief Humidity and temperature driver structure definition

typedef struct

{

HUM_TEMP_StatusTypeDef (*Init)(HUM_TEMP_InitTypeDef *);

HUM_TEMP_StatusTypeDef (*PowerOFF)(void);

HUM_TEMP_StatusTypeDef (*ReadID)(uint8_t *);

HUM_TEMP_StatusTypeDef (*Reset)(void);

void (*ConfigIT)(uint16_t);

void (*EnableIT)(uint8_t);

void (*DisableIT)(uint8_t);

uint8_t (*ITStatus)(uint16_t, uint16_t);