mirror of
https://github.com/m5stack/M5Stack.git
synced 2026-05-20 10:06:46 -07:00
107 lines
3.3 KiB
C++
107 lines
3.3 KiB
C++
#include "DFRobot_SHT20.h"
|
|
|
|
void DFRobot_SHT20::initSHT20(TwoWire &wirePort) {
|
|
i2cPort = &wirePort;
|
|
i2cPort->begin();
|
|
}
|
|
|
|
uint16_t DFRobot_SHT20::readValue(byte cmd) {
|
|
i2cPort->beginTransmission(SLAVE_ADDRESS);
|
|
i2cPort->write(cmd);
|
|
i2cPort->endTransmission();
|
|
byte toRead;
|
|
byte counter;
|
|
for (counter = 0, toRead = 0; counter < MAX_COUNTER && toRead != 3;
|
|
counter++) {
|
|
delay(DELAY_INTERVAL);
|
|
toRead = i2cPort->requestFrom(SLAVE_ADDRESS, 3);
|
|
}
|
|
if (counter == MAX_COUNTER) {
|
|
return (ERROR_I2C_TIMEOUT);
|
|
}
|
|
byte msb, lsb, checksum;
|
|
msb = i2cPort->read();
|
|
lsb = i2cPort->read();
|
|
checksum = i2cPort->read();
|
|
uint16_t rawValue = ((uint16_t)msb << 8) | (uint16_t)lsb;
|
|
if (checkCRC(rawValue, checksum) != 0) {
|
|
return (ERROR_BAD_CRC);
|
|
}
|
|
return rawValue & 0xFFFC;
|
|
}
|
|
|
|
float DFRobot_SHT20::readHumidity(void) {
|
|
uint16_t rawHumidity = readValue(TRIGGER_HUMD_MEASURE_NOHOLD);
|
|
if (rawHumidity == ERROR_I2C_TIMEOUT || rawHumidity == ERROR_BAD_CRC) {
|
|
return (rawHumidity);
|
|
}
|
|
float tempRH = rawHumidity * (125.0 / 65536.0);
|
|
float rh = tempRH - 6.0;
|
|
return (rh);
|
|
}
|
|
|
|
float DFRobot_SHT20::readTemperature(void) {
|
|
uint16_t rawTemperature = readValue(TRIGGER_TEMP_MEASURE_NOHOLD);
|
|
if (rawTemperature == ERROR_I2C_TIMEOUT ||
|
|
rawTemperature == ERROR_BAD_CRC) {
|
|
return (rawTemperature);
|
|
}
|
|
float tempTemperature = rawTemperature * (175.72 / 65536.0);
|
|
float realTemperature = tempTemperature - 46.85;
|
|
return (realTemperature);
|
|
}
|
|
|
|
void DFRobot_SHT20::setResolution(byte resolution) {
|
|
byte userRegister = readUserRegister();
|
|
userRegister &= B01111110;
|
|
resolution &= B10000001;
|
|
userRegister |= resolution;
|
|
writeUserRegister(userRegister);
|
|
}
|
|
|
|
byte DFRobot_SHT20::readUserRegister(void) {
|
|
byte userRegister;
|
|
i2cPort->beginTransmission(SLAVE_ADDRESS);
|
|
i2cPort->write(READ_USER_REG);
|
|
i2cPort->endTransmission();
|
|
i2cPort->requestFrom(SLAVE_ADDRESS, 1);
|
|
userRegister = i2cPort->read();
|
|
return (userRegister);
|
|
}
|
|
|
|
void DFRobot_SHT20::writeUserRegister(byte val) {
|
|
i2cPort->beginTransmission(SLAVE_ADDRESS);
|
|
i2cPort->write(WRITE_USER_REG);
|
|
i2cPort->write(val);
|
|
i2cPort->endTransmission();
|
|
}
|
|
|
|
byte DFRobot_SHT20::checkCRC(uint16_t message_from_sensor,
|
|
uint8_t check_value_from_sensor) {
|
|
uint32_t remainder = (uint32_t)message_from_sensor << 8;
|
|
remainder |= check_value_from_sensor;
|
|
uint32_t divsor = (uint32_t)SHIFTED_DIVISOR;
|
|
for (int i = 0; i < 16; i++) {
|
|
if (remainder & (uint32_t)1 << (23 - i)) {
|
|
remainder ^= divsor;
|
|
}
|
|
divsor >>= 1;
|
|
}
|
|
return (byte)remainder;
|
|
}
|
|
|
|
void DFRobot_SHT20::showReslut(const char *prefix, int val) {
|
|
Serial.print(prefix);
|
|
if (val) {
|
|
Serial.println("yes");
|
|
} else {
|
|
Serial.println("no");
|
|
}
|
|
}
|
|
|
|
void DFRobot_SHT20::checkSHT20(void) {
|
|
byte reg = readUserRegister();
|
|
showReslut("End of battery: ", reg & USER_REGISTER_END_OF_BATTERY);
|
|
showReslut("Heater enabled: ", reg & USER_REGISTER_HEATER_ENABLED);
|
|
showReslut("Disable OTP reload: ", reg & USER_REGISTER_DISABLE_OTP_RELOAD);
|
|
} |