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WIP SHT CRC

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This commit is contained in:
mj 2022-01-02 17:24:08 +01:00
parent e6e97a2547
commit ef18028fe7
3 changed files with 15 additions and 9 deletions
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1
fw/Core/Src/i2c.c
View File

@ -50,6 +50,7 @@ int8_t i2c_receive(uint8_t address, uint8_t *buffer, int len)
{
LL_I2C_HandleTransfer(i2c_context->i2c, address, LL_I2C_ADDRSLAVE_7BIT, len,
LL_I2C_MODE_AUTOEND, LL_I2C_GENERATE_START_READ);
LL_I2C_ClearFlag_STOP(i2c_context->i2c);
int i = 0;
while (!LL_I2C_IsActiveFlag_STOP(i2c_context->i2c)) {
if (LL_I2C_IsActiveFlag_RXNE(i2c_context->i2c)) {

1
fw/Core/Src/scd4x.c
View File

@ -100,7 +100,6 @@ int8_t scd4x_read_measurement(uint16_t *co2, int16_t *temperature, uint16_t *rel
uint8_t t_crc = buffer[5];
uint32_t rh_ticks = (buffer[6] << 8) + buffer[7];
uint8_t rh_crc = buffer[8];
/* check CRC-8 checksum */
uint8_t crc_correct = crc8_calculate(buffer, 2) == co2_crc;
crc_correct &= crc8_calculate(buffer + 3, 2) == t_crc;

22
fw/Core/Src/sht4x.c
View File

@ -23,29 +23,35 @@ int8_t sht4x_measure(int16_t *temperature, uint16_t *relative_humidity)
uint8_t buffer[32];
int result;
// disable interrupts to prevent modbus/i2c conflict
/* disable interrupts to prevent modbus/i2c conflict */
uart_disable_interrupts();
// start measurement
buffer[0] = SHT4X_START_MEAS_HIGH_PRECISION;
result = i2c_transmit(SHT4X_I2C_ADDRESS<<1, buffer, 1);
// TODO: Proc to vraci NACK? Vyresit.
/*
if (result != I2C_OK) {
return SHT4X_ERROR;
}*/
}
uart_enable_interrupts();
LL_mDelay(10); // 10 ms should be enough
LL_mDelay(10); /* 10 ms should be enough */
uart_disable_interrupts();
// read out
/* read out */
result = i2c_receive(SHT4X_I2C_ADDRESS<<1, buffer, 6);
uart_enable_interrupts();
if (result != I2C_OK) {
return SHT4X_ERROR;
}
// TODO checksum
// Convert to T and RH; taken directly from pseudocode in SHT4x datasheet, page 3
/* Convert to T and RH; taken directly from pseudocode in SHT4x datasheet, page 3 */
uint32_t t_ticks = (buffer[0] << 8) + buffer[1];
uint8_t t_crc = buffer[2];
uint32_t rh_ticks = (buffer[3] << 8) + buffer[4];
uint8_t rh_crc = buffer[5];
/* check CRC-8 checksum */
uint8_t crc_correct = crc8_calculate(buffer, 2) == t_crc;
crc_correct &= crc8_calculate(buffer + 3, 2) == rh_crc;
if (!crc_correct) {
return SHT4X_CRC8_ERROR;
}
/* copy data to output variables */
int t_degC = -450 + 10 * 175 * t_ticks / 65535; /* temperature * 10 */
int rh_pRH = -6 + 125 * rh_ticks / 65535;
if (rh_pRH > 100) {