NXP Semiconductors MPC5644A, Reference Manual, Page: 1277 / 1735

Deserial Serial Peripheral Interface (DSPI)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 1277
30.8.2.9 DSPI Transmit FIFO Registers 0–15 (DSPI_TXFR0–DSPI_TXFR15)
The DSPI_TXFR0 – DSPI_TXFR15 registers provide visibility into the TX FIFO for debugging purposes.
Each register is an entry in the TX FIFO. The registers are read-only and cannot be modified. Reading the
DSPI_TXFRx registers does not alter the state of the TX FIFO. The number of registers used to implement
the TX FIFO is device specific. If a four-entry TX FIFO is implemented, DSPI_TXFR0 – DSPI_TXFR3
are accessible.
30.8.2.10 DSPI Receive FIFO Registers 0–15 (DSPI_RXFR0–DSPI_RXFR15)
The DSPI_RXFR0 – DSPI_RXFR15 registers provide visibility into the RX FIFO for debugging
purposes. Each register is an entry in the RX FIFO. The DSPI_RXFR registers are read-only. Reading the
DSPI_RXFRx registers does not alter the state of the RX FIFO. The number of registers used to implement
the RX FIFO is device specific. If a four-entry RX FIFO is implemented, DSPI_RXFR0 – DSPI_RXFR3
exist, for example.
Table 30-16. DSPI_POPR field description
Field Description
0–31
RXDATA[0:31]
Received Data
The RXDATA field contains the SPI data from the RX FIFO entry pointed to by the Pop Next Data
Pointer.
Address: DS0x3C–DS0x78
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
R TXCMD/TXDATA
W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
R TXDATA
W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Figure 30-15. DSPI Transmit FIFO Register 0–15 (DSPI_TXFR0–DSPI_TXFR15)
Table 30-17. DSPI_TXFRn field description
Field Description
0–15
TXCMD[0:15]/
TXDATA[0:15]
Transmit Command or Transmit Data
In master mode the TXCMD field contains the command that sets the transfer attributes for the SPI
data. See
Section 30.8.2.7, DSPI PUSH TX FIFO Register (DSPI_PUSHR) , for details on the
command field. In slave mode the TXDATA contains 16 MSB bits of the SPI data to be shifted out
16–31
TXDATA[16:31]
Transmit Data
The TXDATA field contains the SPI data to be shifted out.