Chapter 20 Deserial Serial Peripheral Interface (DSPI)
MPC5602P Microcontroller Reference Manual, Rev. 4
478
Freescale Semiconductor
20.8.7
Interrupts/DMA requests
The DSPI has conditions that can generate interrupt requests only, and conditions that can generate
interrupts or DMA requests.
lists these conditions.
Each condition has a flag bit and a request enable bit. The flag bits are described in the
“DSPI Status Register (DSPIx_SR)
and the request enable bits are described in the
“DSPI DMA / Interrupt Request Select and Enable Register (DSPIx_RSER)
. The TX FIFO fill flag
(TFFF) and RX FIFO drain flag (RFDF) generate interrupt requests or DMA requests depending on the
TFFF_DIRS and RFDF_DIRS bits in the DSPI
x
_RSER.
20.8.7.1
End of queue interrupt request (EOQF)
The end of queue request indicates that the end of a transmit queue is reached. The end of queue request
is generated when the EOQ bit in the executing SPI command is asserted and the EOQF_RE bit in the
DSPI
x
_RSER is set. Refer to the EOQ bit description in
Section 20.7.2.4, “DSPI Status Register
. Refer to
that illustrate when EOQF is set.
20.8.7.2
Transmit FIFO fill interrupt or DMA request (TFFF)
The transmit FIFO fill request indicates that the TX FIFO is not full. The transmit FIFO fill request is
generated when the number of entries in the TX FIFO is less than the maximum number of possible entries,
and the TFFF_RE bit in the DSPI
x
_RSER is set. The TFFF_DIRS bit in the DSPI
x
_RSER selects whether
a DMA request or an interrupt request is generated.
20.8.7.3
Transfer complete interrupt request (TCF)
The transfer complete request indicates the end of the transfer of a serial frame. The transfer complete
request is generated at the end of each frame transfer when the TCF_RE bit is set in the DSPI
x
_RSER.
Refer to the TCF bit description in
Section 20.7.2.4, “DSPI Status Register (DSPIx_SR)
. Refer to
Table 20-26. Interrupt and DMA request conditions
Condition
Flag
Interrupt
DMA
End of transfer queue has been reached (EOQ)
EOQF
X
TX FIFO is not full
TFFF
X
X
Current frame transfer is complete
TCF
X
TX FIFO underflow has occurred
TFUF
X
RX FIFO is not empty
RFDF
X
X
RX FIFO overflow occurred
RFOF
X
A FIFO overrun occurred
1
1
The FIFO overrun condition is created by ORing the TFUF and RFOF flags together.
TFUF ORed with RFOF
X