Waiting for clearing of busy bit in I2C module of CC2538

Hi,

I am working to connect the CC2538 via I2C to HTU21D temperature and humidity sensor.

When I need to receive the measurement (i.e. receive a sequence of bytes) the datasheet says I should write to I2CM_CTRL register and then wait for the busy bit of I2CM_STAT to be cleared. Doing that didn't work for me, as the BUSY bit was always immediately cleared. Only a short while later the BUSY bit becomes busy and then I can wait for it to be cleared.

Is this behavior normal? According to the CC2538 datasheet at page 442, I should wait for the busy bit immediately after I write to I2CM_CTRL register.

I'd be happy to get an explanation for this behavior.

Here is the relevant piece of code with my workaround:

REG(I2CM_CTRL) = command;
status = REG(I2CM_STAT);
/*** Here is the work around - first wait for the busy bit to become set, in case it is not immediately set  ***/
if ( !(status & I2CM_STAT_BUSY) ) {
        do {
            status = REG(I2CM_STAT);
        } while ( !(status & I2CM_STAT_BUSY));
} 
/*** End of work around ***/
// Wait for busy bit to be cleared
do {
    status = REG(I2CM_STAT);
} while (status & I2CM_STAT_BUSY);