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fix erratic sensor signals

This commit is contained in:
gemu2015 2021-03-30 08:37:50 +02:00
parent 43b9f2bafa
commit 803ecbd9a6
1 changed files with 49 additions and 2 deletions
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51
tasmota/xsns_46_MLX90614.ino
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@ -50,13 +50,15 @@ void MLX90614_Init(void)
void MLX90614_Every_Second(void)
{
mlx90614.i2c_buf = I2cRead24(I2_ADR_IRT, MLX90614_TOBJ1);
//mlx90614.i2c_buf = I2cRead24(I2_ADR_IRT, MLX90614_TOBJ1);
mlx90614.value = MLX90614_read16(I2_ADR_IRT, MLX90614_TOBJ1);
if (mlx90614.value & 0x8000) {
mlx90614.obj_temp = -999;
} else {
mlx90614.obj_temp = ((float)mlx90614.value * 0.02) - 273.15;
}
mlx90614.i2c_buf = I2cRead24(I2_ADR_IRT,MLX90614_TA);
//mlx90614.i2c_buf = I2cRead24(I2_ADR_IRT,MLX90614_TA);
mlx90614.value = MLX90614_read16(I2_ADR_IRT, MLX90614_TA);
if (mlx90614.value & 0x8000) {
mlx90614.amb_temp = -999;
} else {
@ -86,6 +88,51 @@ void MLX90614_Show(uint8_t json)
}
}
uint16_t MLX90614_read16(uint8_t addr, uint8_t a) {
uint16_t ret;
Wire.beginTransmission(addr);
Wire.write(a);
Wire.endTransmission(false);
Wire.requestFrom(addr, (size_t)3);
uint8_t buff[5];
buff[0] = addr << 1;
buff[1] = a;
buff[2] = (addr << 1) | 1;
buff[3] = Wire.read();
buff[4] = Wire.read();
ret = buff[3] | (buff[4] << 8);
uint8_t pec = Wire.read();
uint8_t cpec = MLX90614_crc8(buff, sizeof(buff));
//AddLog(LOG_LEVEL_INFO,PSTR("%x - %x"),pec, cpec);
if (pec != cpec) {
AddLog(LOG_LEVEL_INFO,PSTR("mlx checksum error"));
}
return ret;
}
uint8_t MLX90614_crc8(uint8_t *addr, uint8_t len)
// The PEC calculation includes all bits except the START, REPEATED START, STOP,
// ACK, and NACK bits. The PEC is a CRC-8 with polynomial X8+X2+X1+1.
{
uint8_t crc = 0;
while (len--) {
uint8_t inbyte = *addr++;
for (uint8_t i = 8; i; i--) {
uint8_t carry = (crc ^ inbyte) & 0x80;
crc <<= 1;
if (carry)
crc ^= 0x7;
inbyte <<= 1;
}
}
return crc;
}
/*********************************************************************************************\
* Interface
\*********************************************************************************************/