MCF548x Reference Manual, Rev. 3
27-12 Freescale Semiconductor

Table 27-9. DSR Field Descriptions

Bits Name Description
31 TCF Transfer complete flag. The TCF bit indicates that all bits in a frame have been shifted out.
The TCF bit is set at the end of the frame transfer. The TCF bit remains set until cleared
by software.
0 Transfer not complete
1 Transfer complete
30 TXRXS Transmit and receive status. The TXRXS bit reflects the status of the DSPI. See
Section 27.7.1, “Start and Stop of DSPI Transfers” for information on how what causes this
bit to be negated or asserted.
0 Transmit and receive operations are disabled (DSPI is in Stopped state)
1 Transmit and receive operations are enabled (DSPI is in Running state)
29 — Reserved, should be cleared.
28 EOQF End of queue flag. The EOQF bit indicates that transmission in progress is the last entry
in a queue. The EOQF bit is set when Tx FIFO entry has the EOQ bit set in the command
halfword and the end of the transfer is reached. The EOQF bit remains set until cleared by
software. When the EOQF bit is set, the TXRXS bit is automatically cleared.
0 EOQ is not set in the executing command
1 EOQ is set in the executing SPI command
27 TFUF Transmit FIFO underflow flag. The TFUF bit indicates that an underflow condition in the Tx
FIFO has occurred. The transmit underflow condition is detected only for DSPI blocks
operating in slave mode. The TFUF bit is set when the Tx FIFO of a DSPI operating in slave
mode is empty, and a transfer is initiated by an external SPI master. The TFUF bit remains
set until cleared by software.
0Tx FIFO underflow has not occurred
1Tx FIFO underflow has occurred
26 — Reserved, should be cleared.
25 TFFF Transmit FIFO fill flag. The TFFF bit provides a method for the DSPI to request more
entries to be added to the Tx FIFO. The TFFF bit is set while the Tx FIFO is not full. The
TFFF bit can be cleared by host software or an acknowledgement from the DMA controller
when the Tx FIFO is full.
0Tx FIFO is full
1Tx FIFO is not full
24–20 — Reserved, should be cleared.
19 RFOF Receive FIFO overflow flag. The RFOF bit indicates that an overflow condition in the Rx
FIFO has occurred. The bit is set when the Rx FIFO and shift register are full and a transfer
is initiated. The bit remains set until cleared by software.
0Rx FIFO overflow has not occurred
1Rx FIFO overflow has occurred
18 — Reserved, should be cleared
17 RFDF Receive FIFO drain flag. The RFDF bit provides a method for the DSPI to request that
entries be removed from the Rx FIFO. The bit is set while the Rx FIFO is not empty. The
RFDF bit can be cleared by host software or an acknowledgement from the DMA controller
when the Rx FIFO is empty.
0Rx FIFO is empty
1Rx FIFO is not empty
16 — Reserved, should be cleared.