Changed hts221 into Class.
Dependents: WeatherSensor-Joe PAG-CourseWork-NicksEdits SOFT253_Assignment SOFT253_Assignment_V2 ... more
Fork of hts221 by
hts221.cpp
- Committer:
- kylerodgers
- Date:
- 2015-07-24
- Revision:
- 1:da79e74eadd1
- Parent:
- 0:030da9425166
- Child:
- 2:6d7166d49741
File content as of revision 1:da79e74eadd1:
/* 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" HTS221::HTS221 (PinName sda, PinName scl) : _i2c(sda, scl) { init(); calib(); } bool HTS221::init(void) { bool transfer_succeeded = true; _i2c.frequency(400000); register_write(0x10 , TRes_4 << 3 | HRes_5); register_write(0x20 , PD_On | BDU_On | ODR_1Hz); // Control register 1 register_write(0x21 , NoBoot | HeaterOff | No_OS); // Control register 2 register_write(0x22 , DRDY_H | PP_OD_PP | DRDY_NON); // Control register 3 // Read and verify product ID transfer_succeeded &= verify_product_id(); return transfer_succeeded; } bool HTS221::verify_product_id(void) { char who_am_i[1]; 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]; 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; 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 HTS221::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; }