Memory Map and Registers
MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 27-15

27.6.6 DSPI Tx FIFO Register (DTFR)

The DTFR provides a means to write to the Tx FIFO. SPI commands and data written to this register are

transferred to the Tx FIFO. See Section 27.7.2.4, “Tx FIFO Buffering Mechanism” for more information.

8- or 16-bit write accesses to the DTFR will transfer 32 bits to the Tx FIFO.

SPI Command Field
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
R CONT CTAS EOQ CTCNT 0 0 0 0 CS5 0 CS3 CS2 0 CS0
W
Reset00000 0 0000000000
SPI Data Field
1514131211109876543210
RTXDATA
W
Reset00000 0 0000000000
Reg
Addr
MBAR + 0x8A34

Figure 27-7. DSPI Tx FIFO Register (DTFR)

Table 27-10. DTFR Field Descriptions

Bits Name Description
31 CONT Continuous peripheral chip select enable. The CONT bit selects a continuous selection format.
The bit is used in SPI master mode. The bit enables the selected DSPICSn signals to remain
asserted between transfers. See Section 27.7.4.5, “Continuous Selection Format' for more
information.
0 DSPICSn signals return to their inactive state between transfers
1 DSPICSn signals stay asserted between transfers
30–28 CTAS Clock and transfer attributes select. The CTAS field selects which of the DCTAR registers is used
to set the transfer attributes for the associated SPI frame. The field is only used in SPI master
mode. In SPI slave mode DCTAR0 is used. The number of DSPI_CTAR registers is
implementation specific.
000 DCTAR0 determines clock and attributes for transfer
001 DCTAR1 determines clock and attributes for transfer
010 DCTAR2 determines clock and attributes for transfer
011 DCTAR3 determines clock and attributes for transfer
100 DCTAR4 determines clock and attributes for transfer
101 DCTAR5 determines clock and attributes for transfer
110 DCTAR6 determines clock and attributes for transfer
111 DCTAR7 determines clock and attributes for transfer
27 EOQ End of queue. The EOQ bit provides a means for host software to signal to the DSPI that the
current SPI transfer is the last in a queue. At the end of the transfer the EOQF bit in the DSR is set.
0 The SPI data is not the last data to transfer
1 The SPI data is the last data to transfer