Hi,
I've been trying to read temperature values from AD7414 sensor over I2C bus. To read 10-bit temperature value one need to set address register to 0x00. After that two byte read operation is needed to read temperature.
Here's my code:
GPIOPinTypeI2C(TEMP_SDA_PORT, TEMP_SDA_PIN);
GPIOPinTypeI2CSCL(TEMP_SCL_PORT, TEMP_SCL_PIN);
I2CMasterEnable(I2C2_BASE);
I2CMasterInitExpClk(I2C2_BASE, SysCtlClockGet(), false);
I2CRxFIFOConfigSet(I2C2_BASE, I2C_FIFO_CFG_RX_MASTER);
SysCtlDelay(20000);
while(1)
{
uint8_t i2c_data[8] = {0};
uint8_t i;
I2CMasterSlaveAddrSet(I2C2_BASE, TEMP_I2C_ADDRESS, false);
I2CMasterDataPut(I2C2_BASE, 0x00);
I2CMasterControl(I2C2_BASE, I2C_MASTER_CMD_SINGLE_SEND);
while(I2CMasterBusy(I2C2_BASE));
SysCtlDelay(20000);
I2CMasterSlaveAddrSet(I2C2_BASE, TEMP_I2C_ADDRESS, true);
I2CMasterBurstLengthSet(I2C2_BASE, 2);
I2CMasterControl(I2C2_BASE, I2C_MASTER_CMD_FIFO_BURST_RECEIVE_START);
while(I2CMasterBusy(I2C2_BASE));
I2CMasterControl(I2C2_BASE, I2C_MASTER_CMD_FIFO_BURST_RECEIVE_FINISH);
for(i = 0; i < 8; i++)
{
if(I2CFIFODataGetNonBlocking(I2C2_BASE, &i2c_data[i]) == 0)
{
break;
}
}
I2CRxFIFOFlush(I2C2_BASE);
SysCtlDelay(200000);
}
Obviously it's not working as it should.
Here's what I'm getting on a scope:
There's a garbage read after first NACK indicating end of transmission. I would not be too bad, because values of 0x1C and 0xA0 are read along with those two 0xFFs.
Unfortunately, many times burst read just does not occur and I read nothing:
