I have discovered some disrepancy. I am debugging my program on BF504F. Hardware Manual for BF504 contains description of modem status (UARTx_MSR) registers which contains information about state of 4-deep receive FIFO. But VisualDSP++ doesn't show this register. Futhermore, it displays 0xeeeeeeee at memory address of this register. Is it really present in BF504F or not? And how to exemine status of receive FIFO?