altb_pmic / Mbed 2 deprecated Grove-Barometric_Pressure_Sensor_Example

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

Dependencies:   HP206C mbed

main.cpp@1:a6eded1f5043, 2019-06-25 (annotated)

Committer:
pmic
Date:
Tue Jun 25 11:46:33 2019 +0000
Revision:
1:a6eded1f5043
Parent:
0:5119eeafd9ce
Child:
2:ecd5c6118888
first adjustments

Who changed what in which revision?

UserRevisionLine numberNew contents of line
pmic 0:5119eeafd9ce 1 #include "mbed.h"
pmic 0:5119eeafd9ce 2
pmic 1:a6eded1f5043 3 #define I2C_BAROMETER_ADDRESS 0x76 << 1 // 0xEC, device adress
pmic 1:a6eded1f5043 4
pmic 1:a6eded1f5043 5 #define HP20X_SOFT_RST 0x06 // for initializing, takes longer than next
pmic 1:a6eded1f5043 6 #define HP20X_ANA_CAL 0x28 // recalibrate analog internal circuitries, for unstable environment
pmic 1:a6eded1f5043 7
pmic 0:5119eeafd9ce 8 #define HP20X_WR_CONVERT_CMD 0x40
pmic 1:a6eded1f5043 9
pmic 1:a6eded1f5043 10 #define HP20X_READ_PT 0x10 // read pressure and altitude command
pmic 1:a6eded1f5043 11 #define HP20X_READ_A 0x31 // read altitude command
pmic 1:a6eded1f5043 12
pmic 1:a6eded1f5043 13 #define HP20X_WR_REG_MODE 0xC0
pmic 1:a6eded1f5043 14 #define HP20X_RD_REG_MODE 0x80
pmic 1:a6eded1f5043 15
pmic 1:a6eded1f5043 16 #define HP20X_OK_DEV 0X80 // successfully initialized
pmic 1:a6eded1f5043 17 #define HP20X_REG_PARA 0X0F // status register
pmic 1:a6eded1f5043 18
pmic 0:5119eeafd9ce 19 #define HP20X_CONVERT_OSR4096 0 << 2
pmic 0:5119eeafd9ce 20 #define HP20X_CONVERT_OSR2048 1 << 2
pmic 0:5119eeafd9ce 21 #define HP20X_CONVERT_OSR1024 2 << 2
pmic 0:5119eeafd9ce 22 #define HP20X_CONVERT_OSR512 3 << 2
pmic 0:5119eeafd9ce 23 #define HP20X_CONVERT_OSR256 4 << 2
pmic 0:5119eeafd9ce 24 #define HP20X_CONVERT_OSR128 5 << 2
pmic 0:5119eeafd9ce 25
pmic 1:a6eded1f5043 26 #define OSR_CFG HP20X_CONVERT_OSR1024
pmic 0:5119eeafd9ce 27
pmic 0:5119eeafd9ce 28 Serial serial(SERIAL_TX, SERIAL_RX);
pmic 0:5119eeafd9ce 29 I2C i2c(I2C_SDA, I2C_SCL); // PB_9, PB_8
pmic 0:5119eeafd9ce 30
pmic 0:5119eeafd9ce 31 float temperature = 0.0f;
pmic 0:5119eeafd9ce 32 float pressure = 0.0f;
pmic 0:5119eeafd9ce 33 float altitude = 0.0f;
pmic 0:5119eeafd9ce 34 bool baro_found = false;
pmic 0:5119eeafd9ce 35
pmic 0:5119eeafd9ce 36 typedef enum {
pmic 0:5119eeafd9ce 37 HP20X_READ_TEMP,
pmic 0:5119eeafd9ce 38 HP20X_READ_PRES
pmic 0:5119eeafd9ce 39 } barometerReadingType;
pmic 0:5119eeafd9ce 40
pmic 0:5119eeafd9ce 41 // send a register reading command
pmic 0:5119eeafd9ce 42 unsigned char readRegister(unsigned char reg) {
pmic 0:5119eeafd9ce 43 char i2cBuffer[1];
pmic 0:5119eeafd9ce 44 i2cBuffer[0] = (reg | HP20X_RD_REG_MODE);
pmic 0:5119eeafd9ce 45 i2c.write(I2C_BAROMETER_ADDRESS, i2cBuffer, 1);
pmic 0:5119eeafd9ce 46
pmic 0:5119eeafd9ce 47 // read the data
pmic 0:5119eeafd9ce 48 i2c.read(I2C_BAROMETER_ADDRESS, i2cBuffer, 1);
pmic 0:5119eeafd9ce 49
pmic 0:5119eeafd9ce 50 return i2cBuffer[0];
pmic 0:5119eeafd9ce 51 }
pmic 0:5119eeafd9ce 52
pmic 0:5119eeafd9ce 53 // send a register writing command
pmic 0:5119eeafd9ce 54 void writeRegister(unsigned char reg, unsigned char data) {
pmic 0:5119eeafd9ce 55 char i2cBuffer[1];
pmic 0:5119eeafd9ce 56 i2cBuffer[0] = (reg | HP20X_WR_REG_MODE);
pmic 0:5119eeafd9ce 57 i2c.write(I2C_BAROMETER_ADDRESS, i2cBuffer, 1);
pmic 0:5119eeafd9ce 58 i2cBuffer[0] = data;
pmic 0:5119eeafd9ce 59 i2c.write(I2C_BAROMETER_ADDRESS, i2cBuffer, 1);
pmic 0:5119eeafd9ce 60 }
pmic 0:5119eeafd9ce 61
pmic 0:5119eeafd9ce 62 void enableCompensation() {
pmic 0:5119eeafd9ce 63 writeRegister(HP20X_REG_PARA, 0x01);
pmic 0:5119eeafd9ce 64 }
pmic 0:5119eeafd9ce 65
pmic 0:5119eeafd9ce 66 void disableCompensation() {
pmic 0:5119eeafd9ce 67 writeRegister(HP20X_REG_PARA, 0x00);
pmic 0:5119eeafd9ce 68 }
pmic 0:5119eeafd9ce 69
pmic 0:5119eeafd9ce 70 void softReset() {
pmic 0:5119eeafd9ce 71 char i2cBuffer[1];
pmic 0:5119eeafd9ce 72 i2cBuffer[0] = HP20X_SOFT_RST;
pmic 0:5119eeafd9ce 73 i2c.write(I2C_BAROMETER_ADDRESS, i2cBuffer, 1);
pmic 0:5119eeafd9ce 74 }
pmic 0:5119eeafd9ce 75
pmic 0:5119eeafd9ce 76 void recalibrate() {
pmic 0:5119eeafd9ce 77 char i2cBuffer[1];
pmic 0:5119eeafd9ce 78 i2cBuffer[0] = HP20X_ANA_CAL;
pmic 0:5119eeafd9ce 79 i2c.write(I2C_BAROMETER_ADDRESS, i2cBuffer, 1);
pmic 0:5119eeafd9ce 80 }
pmic 0:5119eeafd9ce 81
pmic 0:5119eeafd9ce 82 uint32_t readData3Bytes() {
pmic 0:5119eeafd9ce 83 uint32_t tmpData;
pmic 0:5119eeafd9ce 84 char tmpArray[3] = {0};
pmic 0:5119eeafd9ce 85
pmic 0:5119eeafd9ce 86 // request 3 bytes from device
pmic 0:5119eeafd9ce 87 i2c.read(I2C_BAROMETER_ADDRESS, tmpArray, 3);
pmic 0:5119eeafd9ce 88
pmic 0:5119eeafd9ce 89 // MSB
pmic 0:5119eeafd9ce 90 tmpData = tmpArray[0] << 16 | tmpArray[1] << 8 | tmpArray[2];
pmic 0:5119eeafd9ce 91
pmic 0:5119eeafd9ce 92 if(tmpData & 0x800000) {
pmic 0:5119eeafd9ce 93 tmpData |= 0xff000000;
pmic 0:5119eeafd9ce 94 }
pmic 0:5119eeafd9ce 95
pmic 0:5119eeafd9ce 96 return tmpData;
pmic 0:5119eeafd9ce 97 }
pmic 0:5119eeafd9ce 98
pmic 0:5119eeafd9ce 99 uint32_t *readData6Bytes() {
pmic 0:5119eeafd9ce 100 static uint32_t tmpData[2];
pmic 0:5119eeafd9ce 101 char tmpArray[6] = {0};
pmic 0:5119eeafd9ce 102
pmic 0:5119eeafd9ce 103 // request 6 bytes from device
pmic 0:5119eeafd9ce 104 i2c.read(I2C_BAROMETER_ADDRESS, tmpArray, 6);
pmic 0:5119eeafd9ce 105
pmic 0:5119eeafd9ce 106 // MSB
pmic 0:5119eeafd9ce 107 tmpData[0] = tmpArray[0] << 16 | tmpArray[1] << 8 | tmpArray[2]; // temperature
pmic 0:5119eeafd9ce 108 tmpData[1] = tmpArray[3] << 16 | tmpArray[4] << 8 | tmpArray[5]; // pressure
pmic 0:5119eeafd9ce 109
pmic 0:5119eeafd9ce 110 if(tmpData[0] & 0x800000) {
pmic 0:5119eeafd9ce 111 tmpData[0] |= 0xff000000;
pmic 0:5119eeafd9ce 112 }
pmic 0:5119eeafd9ce 113 if(tmpData[1] & 0x800000) {
pmic 0:5119eeafd9ce 114 tmpData[1] |= 0xff000000;
pmic 0:5119eeafd9ce 115 }
pmic 0:5119eeafd9ce 116
pmic 0:5119eeafd9ce 117 return tmpData;
pmic 0:5119eeafd9ce 118 }
pmic 0:5119eeafd9ce 119
pmic 0:5119eeafd9ce 120 void readTemperatureAndPressureStep1() {
pmic 0:5119eeafd9ce 121 char i2cBuffer[2];
pmic 0:5119eeafd9ce 122 i2cBuffer[0] = HP20X_WR_CONVERT_CMD | OSR_CFG;
pmic 0:5119eeafd9ce 123 i2c.write(I2C_BAROMETER_ADDRESS, i2cBuffer, 1); // ADC convert
pmic 0:5119eeafd9ce 124 }
pmic 0:5119eeafd9ce 125
pmic 0:5119eeafd9ce 126 void readTemperatureAndPressureStep2() {
pmic 0:5119eeafd9ce 127 char i2cBuffer[1];
pmic 0:5119eeafd9ce 128
pmic 0:5119eeafd9ce 129 i2cBuffer[0] = HP20X_READ_PT;
pmic 0:5119eeafd9ce 130 i2c.write(I2C_BAROMETER_ADDRESS, i2cBuffer, 1);
pmic 0:5119eeafd9ce 131
pmic 0:5119eeafd9ce 132 uint32_t *p = readData6Bytes();
pmic 0:5119eeafd9ce 133 temperature = ((double)p[0] / 100.0f);
pmic 0:5119eeafd9ce 134 pressure = ((double)p[1] / 100.0f);
pmic 0:5119eeafd9ce 135 }
pmic 0:5119eeafd9ce 136
pmic 0:5119eeafd9ce 137 void readAltitude() {
pmic 0:5119eeafd9ce 138 char i2cBuffer[1];
pmic 0:5119eeafd9ce 139 i2cBuffer[0] = HP20X_READ_A;
pmic 0:5119eeafd9ce 140 i2c.write(I2C_BAROMETER_ADDRESS, i2cBuffer, 1);
pmic 0:5119eeafd9ce 141
pmic 0:5119eeafd9ce 142 altitude = ((double)readData3Bytes() / 100.0f);
pmic 0:5119eeafd9ce 143 }
pmic 0:5119eeafd9ce 144
pmic 0:5119eeafd9ce 145 // calculate the conversion time needed before reading back the sensor values
pmic 0:5119eeafd9ce 146 uint8_t getConversionTime(barometerReadingType type) {
pmic 0:5119eeafd9ce 147 uint32_t OSR_ConvertTime;
pmic 0:5119eeafd9ce 148 if (OSR_CFG == HP20X_CONVERT_OSR128) {
pmic 0:5119eeafd9ce 149 switch (type) {
pmic 0:5119eeafd9ce 150 case HP20X_READ_TEMP: OSR_ConvertTime = 3; break; // 2.1 ms
pmic 0:5119eeafd9ce 151 case HP20X_READ_PRES: OSR_ConvertTime = 5; break; // 4.1 ms
pmic 0:5119eeafd9ce 152 }
pmic 0:5119eeafd9ce 153 } else if (OSR_CFG == HP20X_CONVERT_OSR256) {
pmic 0:5119eeafd9ce 154 switch (type) {
pmic 0:5119eeafd9ce 155 case HP20X_READ_TEMP: OSR_ConvertTime = 5; break; // 4.1 ms
pmic 0:5119eeafd9ce 156 case HP20X_READ_PRES: OSR_ConvertTime = 9; break; // 8.2 ms
pmic 0:5119eeafd9ce 157 }
pmic 0:5119eeafd9ce 158 } else if (OSR_CFG == HP20X_CONVERT_OSR512) {
pmic 0:5119eeafd9ce 159 switch (type) {
pmic 0:5119eeafd9ce 160 case HP20X_READ_TEMP: OSR_ConvertTime = 9; break; // 8.2 ms
pmic 0:5119eeafd9ce 161 case HP20X_READ_PRES: OSR_ConvertTime = 17; break; // 16.4 ms
pmic 0:5119eeafd9ce 162 }
pmic 0:5119eeafd9ce 163 } else if (OSR_CFG == HP20X_CONVERT_OSR1024) {
pmic 0:5119eeafd9ce 164 switch (type) {
pmic 0:5119eeafd9ce 165 case HP20X_READ_TEMP: OSR_ConvertTime = 17; break; // 16.4 ms
pmic 0:5119eeafd9ce 166 case HP20X_READ_PRES: OSR_ConvertTime = 34; break; // 32.8 ms
pmic 0:5119eeafd9ce 167 }
pmic 0:5119eeafd9ce 168 } else if (OSR_CFG == HP20X_CONVERT_OSR2048) {
pmic 0:5119eeafd9ce 169 switch (type) {
pmic 0:5119eeafd9ce 170 case HP20X_READ_TEMP: OSR_ConvertTime = 34; break; // 32.8 ms
pmic 0:5119eeafd9ce 171 case HP20X_READ_PRES: OSR_ConvertTime = 67; break; // 65.6 ms
pmic 0:5119eeafd9ce 172 }
pmic 0:5119eeafd9ce 173 } else if (OSR_CFG == HP20X_CONVERT_OSR4096) {
pmic 0:5119eeafd9ce 174 switch (type) {
pmic 0:5119eeafd9ce 175 case HP20X_READ_TEMP: OSR_ConvertTime = 67; break; // 65.6 ms
pmic 0:5119eeafd9ce 176 case HP20X_READ_PRES: OSR_ConvertTime = 132; break; // 131.1 ms
pmic 0:5119eeafd9ce 177 }
pmic 0:5119eeafd9ce 178 }
pmic 0:5119eeafd9ce 179
pmic 0:5119eeafd9ce 180 return OSR_ConvertTime;
pmic 0:5119eeafd9ce 181 }
pmic 0:5119eeafd9ce 182
pmic 0:5119eeafd9ce 183 int main()
pmic 0:5119eeafd9ce 184 {
pmic 0:5119eeafd9ce 185 serial.baud(115200);
pmic 0:5119eeafd9ce 186 i2c.frequency((uint32_t)100e3);
pmic 0:5119eeafd9ce 187
pmic 0:5119eeafd9ce 188 serial.printf("HP206C barometer example...\n");
pmic 0:5119eeafd9ce 189
pmic 0:5119eeafd9ce 190 // detect the barometer
pmic 0:5119eeafd9ce 191 unsigned char result = readRegister(HP20X_REG_PARA);
pmic 0:5119eeafd9ce 192 if (result == HP20X_OK_DEV) {
pmic 0:5119eeafd9ce 193 baro_found = true;
pmic 0:5119eeafd9ce 194 softReset();
pmic 1:a6eded1f5043 195 // recalibrate();
pmic 0:5119eeafd9ce 196 disableCompensation();
pmic 1:a6eded1f5043 197 // enableCompensation();
pmic 0:5119eeafd9ce 198 serial.printf("barometer found\n");
pmic 0:5119eeafd9ce 199 } else {
pmic 0:5119eeafd9ce 200 serial.printf("barometer NOT found \n");
pmic 0:5119eeafd9ce 201 while(1);
pmic 0:5119eeafd9ce 202 }
pmic 0:5119eeafd9ce 203
pmic 0:5119eeafd9ce 204 while(1)
pmic 0:5119eeafd9ce 205 {
pmic 0:5119eeafd9ce 206 if (baro_found) {
pmic 1:a6eded1f5043 207 // recalibrate();
pmic 1:a6eded1f5043 208 // wait_us(70); // this delay is a must if we read temperature, pressure or altitude right after the recalibration (in tests, 60 didn't worked) in microseconds
pmic 0:5119eeafd9ce 209 readTemperatureAndPressureStep1();
pmic 0:5119eeafd9ce 210 wait_ms(getConversionTime(HP20X_READ_PRES)); // get only the pressure, because its the longest interval
pmic 0:5119eeafd9ce 211 readTemperatureAndPressureStep2();
pmic 0:5119eeafd9ce 212 readAltitude();
pmic 0:5119eeafd9ce 213
pmic 1:a6eded1f5043 214 //serial.printf("temperature %f, pressure %f, altitude %f\r\n", temperature, pressure, altitude);
pmic 1:a6eded1f5043 215 serial.printf("altitude %f\r\n", altitude);
pmic 1:a6eded1f5043 216 // wait_ms(1); // don't hammer the serial console
pmic 0:5119eeafd9ce 217 }
pmic 0:5119eeafd9ce 218 }
pmic 0:5119eeafd9ce 219 }