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DMA Serial Peripheral Interface (DSPI)
Freescale Semiconductor
31-7
25
PCSSE
Peripheral chip select strobe enable. Selects between the DSPI_PCS5 and DSPI_PCSS functions on the
DSPI_PCS5/PCSS signal. See
Section 31.4.3.5, “Peripheral Chip Select Strobe Enable (PCSS)
,” for more
information.
0 DSPI_PCS5/PCSS is used as the peripheral chip select 5 signal
1 DSPI_PCS5/PCSS is used as an active-low PCS strobe signal
24
ROOE
Receive FIFO overflow overwrite enable. Enables an RX FIFO overflow condition to ignore the incoming serial data
or to overwrite existing data. If the RX FIFO is full and new data is received, data from the transfer that generated
the overflow is ignored or shifted in to the shift register. If the ROOE bit is set, incoming data is shifted into the shift
register. If the ROOE bit is cleared, incoming data is ignored. See
Section 31.4.6.6, “Receive FIFO Overflow Interrupt
,” for more information.
0 Incoming data is ignored
1 Incoming data is shifted in to the shift register
23–16
PCSIS
n
Peripheral chip select inactive state. Determines the inactive state of the DSPI_PCS
n
signal.
0 The inactive state of DSPI_PCS
n
is low
1 The inactive state of DSPI_PCS
n
is high
Note:
DSPI_PCS7, DSPI_PCS6, and DSPI_PCS4 are not implemented on this device. Therefore, these
corresponding bits are reserved.
Note:
DSPI_PCS0/SS must be configured as inactive high for slave mode operation.
15
Reserved, must be cleared.
14
MDIS
Module disable. Allows the clock to be stopped to non-memory mapped logic in DSPI effectively putting DSPI in a
software controlled power-saving state. See
Section 31.4.7, “Power Saving Features,”
for more information. This bit
is set at reset.
0 Enable DSPI clocks
1 Allow external logic to disable DSPI clocks
13
DIS_TXF
Disable transmit FIFO. When the TX FIFO is disabled, transmit part of the DSPI operates as a simplified
double-buffered SPI. See
Section 31.4.2.3, “FIFO Disable Operation,”
for details.
0 TX FIFO is enabled
1 TX FIFO is disabled
12
DIS_RXF
Disable receive FIFO. When the RX FIFO is disabled, receive part of the DSPI operates as a simplified
double-buffered SPI. See
Section 31.4.2.3, “FIFO Disable Operation
for details.”
0 RX FIFO is enabled
1 RX FIFO is disabled
11
CLR_TXF
Clear TX FIFO. Flushes the TX FIFO. The CLR_TXF bit is always read as zero.
0 Do not clear the TX FIFO counter
1 Clear the TX FIFO counter
Note:
When the respective FIFO is disabled, this bit does has no effect.
10
CLR_RXF
Clear RX FIFO. Flushes the RX FIFO. The CLR_RXF bit is always read as zero.
0 Do not clear the RX FIFO counter
1 Clear the RX FIFO counter
Note:
When the respective FIFO is disabled, this bit does has no effect.
9–8
SMPL_PT
Sample point. Allows host software to select when the DSPI master samples SIN in modified transfer format.
shows where the master can sample the SIN pin.
00 0 system clocks between DSPI_SCK edge and DSPI_SIN sample
01 1 system clock between DSPI_SCK edge and DSPI_SIN sample
10 2 system clocks between DSPI_SCK edge and DSPI_SIN sample
11 Reserved
Table 31-3. DSPI_MCR Field Descriptions (continued)
Field
Description
Содержание MCF54455
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