Changed hts221 into Class.
Dependents: WeatherSensor-Joe PAG-CourseWork-NicksEdits SOFT253_Assignment SOFT253_Assignment_V2 ... more
Fork of hts221 by
Diff: hts221.cpp
- Revision:
- 0:030da9425166
- Child:
- 1:da79e74eadd1
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hts221.cpp Fri Jan 30 08:49:01 2015 +0000 @@ -0,0 +1,163 @@ +/* Copyright (c) 2009 Nordic Semiconductor. All Rights Reserved. + * + * The information contained herein is property of Nordic Semiconductor ASA. + * Terms and conditions of usage are described in detail in NORDIC + * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT. + * + * Licensees are granted free, non-transferable use of the information. NO + * WARRANTY of ANY KIND is provided. This heading must NOT be removed from + * the file. + *df + */ + +#include <stdbool.h> +#include <stdint.h> + +#include <mbed.h> +#include "hts221.h" + +I2C i2c(p22, p20); //SDA, SCL + + +/*lint ++flb "Enter library region" */ + +// Gill + + +// + +static const char expected_who_am_i = 0xBCU; //!< Expected value to get from WHO_AM_I register. + +uint8_t H0_rH_x2; +uint8_t H1_rH_x2; +uint16_t T0_degC_x8; +uint16_t T1_degC_x8; + +int16_t H0_T0_OUT; +int16_t H1_T0_OUT; +int16_t T0_OUT; +int16_t T1_OUT; + +float T0_DegC_cal; +float T1_DegC_cal; +float H0_RH_cal; +float H1_RH_cal; + +bool hts221_init(void) +{ + bool transfer_succeeded = true; + + i2c.frequency(400000); + hts221_register_write(0x10 , TRes_4 << 3 | HRes_5); + hts221_register_write(0x20 , PD_On | BDU_On | ODR_1Hz); // Control register 1 + hts221_register_write(0x21 , NoBoot | HeaterOff | No_OS); // Control register 2 + hts221_register_write(0x22 , DRDY_H | PP_OD_PP | DRDY_NON); // Control register 3 + + // Read and verify product ID + transfer_succeeded &= hts221_verify_product_id(); + + return transfer_succeeded; +} + +bool hts221_verify_product_id(void) +{ + char who_am_i[1]; + hts221_register_read(ADDRESS_WHO_AM_I, &who_am_i[0], 1); + if (who_am_i[0] != expected_who_am_i) return false; + else return true; +} + +void hts221_register_write(uint8_t register_address, uint8_t value) +{ + char w2_data[2]; + + w2_data[0] = register_address; + w2_data[1] = value; + i2c.write(HTS221_WriteADDE, w2_data, 2); + +} + +void hts221_register_read(char register_address, char *destination, uint8_t number_of_bytes) +{ + i2c.write(HTS221_WriteADDE, ®ister_address, 1, 1); + i2c.read(HTS221_WriteADDE, destination, number_of_bytes); //Note by Tsungta, API may have a bug + + //runaboud read function added by Tsungta +/* if (number_of_bytes == 1) { + i2c.write(HTS221_WriteADDE, ®ister_address, 1, 1); + i2c.write(HTS221_ReadADDE); + *destination = i2c.read(0); + i2c.stop(); + } else { + register_address |= 0x80; + i2c.write(HTS221_WriteADDE, ®ister_address, 1, 1); + i2c.write(HTS221_ReadADDE); + while (number_of_bytes-- > 0) + *destination++ = i2c.read(0); + i2c.stop(); + }*/ +} + +void HTS221_Calib(void) +{ + char cal_data[16]; + + hts221_register_read(0xB0, cal_data, 16); + + H0_rH_x2 = cal_data[0]; + H1_rH_x2 = cal_data[1]; + T0_degC_x8 = ((cal_data[5] & 0x03) << 8) + cal_data[2]; //MSB + LSB in + T1_degC_x8 = ((cal_data[5] & 0x0C) << 6) + cal_data[3]; // MSB + + H0_T0_OUT = (cal_data[7] << 8) + cal_data[6]; + H1_T0_OUT = (cal_data[11] << 8) + cal_data[10]; + T0_OUT = (cal_data[13] << 8) + cal_data[12]; + T1_OUT = (cal_data[15] << 8) + cal_data[14]; + + // convert negative 2's complement values to native negative value + if (H0_T0_OUT&0x8000) H0_T0_OUT = -(0x8000-(0x7fff&H0_T0_OUT)); + if (H1_T0_OUT&0x8000) H1_T0_OUT = -(0x8000-(0x7fff&H1_T0_OUT)); //((~H1_T0_OUT)+1);// + if (T0_OUT&0x8000) T0_OUT = -(0x8000-(0x7fff&T0_OUT)); + if (T1_OUT&0x8000) T1_OUT = -(0x8000-(0x7fff&T1_OUT)); + + T0_DegC_cal = (float) T0_degC_x8/8; + T1_DegC_cal = (float) T1_degC_x8/8; + H0_RH_cal = (float) H0_rH_x2/2; + H1_RH_cal = (float) H1_rH_x2/2; + +} + +void HTS221_ReadTempHumi( float *pTemp , float *pHumi) +{ + char sensor_data[4]; + int16_t H_OUT; + int16_t T_OUT; + + hts221_register_read(0xA8, sensor_data, 4); + + H_OUT = (sensor_data[1] << 8) + sensor_data[0]; + T_OUT = (sensor_data[3] << 8) + sensor_data[2]; + + // convert negative 2's complement values to native negative value + if (H_OUT&0x8000) H_OUT = -(0x8000-(0x7fff&H_OUT)); //((~H_OUT)+1);; + if (T_OUT&0x8000) T_OUT = -(0x8000-(0x7fff&T_OUT)); + + *pTemp = linear_interpolation(T0_OUT, T0_DegC_cal, T1_OUT, T1_DegC_cal, T_OUT); + *pHumi = linear_interpolation(H0_T0_OUT, H0_RH_cal, H1_T0_OUT, H1_RH_cal, H_OUT); + // Constraint for measurement after calibration + if ((int)*pHumi>MaxHumi-1 | (int)*pHumi==-72) *pHumi = MaxHumi; + if ((int)*pHumi<MinHumi ) *pHumi = MinHumi; + if ((int)*pTemp>MaxTemp-1) *pHumi = MaxTemp; + if ((int)*pHumi<MinTemp ) *pHumi = MinTemp ; +} + +float linear_interpolation(int16_t x0, float y0, int16_t x1, float y1, float mes) +{ + float a = (float) ((y1 - y0) / (x1 - x0)); + float b = (float) -a*x0 + y0; + float cal = (float) a * mes + b; + return cal; +} + +/*lint --flb "Leave library region" */ +