Freescale Semiconductor MCF54455 Reference Manual page 765

DMA Serial Peripheral Interface (DSPI)
Field
17–16 Baud rate prescaler. Selects the prescaler value for the baud rate. This field is only used in master mode. The baud
PBR rate is the frequency of the serial communications clock (DSPI_SCK). The system clock is divided by the prescaler
value before the baud rate selection takes place. The description for
how to compute the baud rate.
00 2 clock prescaler to divide system clock
01 3 clock prescaler to divide system clock
10 5 clock prescaler to divide system clock
11 7 clock prescaler to divide system clock
15–12 PCS to SCK delay scaler. Selects the scaler value for the PCS to SCK delay. This field is only used in master mode.
CSSCK The PCS to SCK delay is the delay between the assertion of DSPI_PCS and the first edge of the DSPI_SCK. The
table below lists the scaler values.
Note: When the continuous selection format is selected (CONT or DCONT is set), switching the PCS to SCK delay
prescaler without stopping the DSPI can cause errors in the transfer.
Note: See Section 31.4.3.2, "PCS to SCK Delay
31-12
Table 31-5. DSPI_CTARn Field Description (continued)
PCS to SCK Delay
CSSCK
Scaler Value
0000 2
0001 4
0010 8
0011 16
0100 32
0101 64
0110 128
0111 256
Description
Section 31.4.3.1, "Baud Rate
PCS to SCK Delay
CSSCK
1000
1001
1010
1011
1100
1101
1110
1111
(tCSC)," for details on calculating the PCS to SCK delay.
Generator" details
Scaler Value
512
1024
2048
4096
8192
16384
32768
65536
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