Hi,
When reading the FIFO buffer through I2C read command, we typically retrieve 6 bytes of data: 3 bytes for the Red LED value and 3 bytes for the IR LED value.
The question is: how is the data arranged in the 6-byte buffer?
Is it organized such that bytes 0 to 2 represent the Red LED data, and bytes 3 to 5 represent the IR LED data?
I also noticed that some MAX30102 firmware driver using bytes 0 to 2 represent the raw IR LED data, 3 to 5 represent LED raw data and vice versa.
I'm a bit confused about how the data is arranged when reading multiple bytes. Could you clarify the orientation of the data in the buffer?
void MAX301ReadFifoNew(void)
{
uint32_t irBuff[32];
uint32_t redBuff[32];
// Get 32 samples of data
for (int8_t i = 0; i < 32; i++)
{
uint8_t address;
uint8_t buf[6];
uint8_t numBytes = 6; // Buffer for IR (3 bytes) + RED (3 bytes)
I2C_HandleTypeDef i2cHandle = GetI2cHandle(MAX301_I2C_NUM);
buf[0] = FIFO_DATA;
address = (I2C_SLAVE_ID | I2C_WRITE);
HAL_I2C_Master_Transmit(&i2cHandle, address, buf, 1, HAL_MAX_DELAY);
address = (I2C_SLAVE_ID | I2C_READ);
HAL_I2C_Master_Receive(&i2cHandle, address, buf, numBytes, HAL_MAX_DELAY);
// uint32_t irSample = ((uint32_t)(buf[0] << 16) | (uint32_t)(buf[1] << | (uint32_t)(buf[2])) & 0x3ffff;
// uint32_t redSample = ((uint32_t)(buf[3] << 16) | (uint32_t)(buf[4] << | (uint32_t)(buf[5])) & 0x3ffff;
uint32_t redSample = ((uint32_t)(buf[0] << 16) | (uint32_t)(buf[1] << | (uint32_t)(buf[2])) & 0x3ffff;
uint32_t irSample = ((uint32_t)(buf[3] << 16) | (uint32_t)(buf[4] << | (uint32_t)(buf[5])) & 0x3ffff;
irBuff[i] = irSample;
redBuff[i] = redSample;
}
DEBUG_PRINTF("Read FIFO end...");
}
