ST SPC560P34 - Page 450

Deserial Serial Peripheral Interface (DSPI) RM0046
450/936 Doc ID 16912 Rev 5
14–15
PBR[0:1]
Baud Rate Prescale
The PBR field selects the prescaler value for the baud rate. This field is only used in Master
Mode. The baud rate is the frequency of the Serial Communications Clock (SCK). The system
clock is divided by the prescaler value before the baud rate selection takes place. The baud rate
prescaler values are listed in the table. See the BR[0:3] field description for details on how to
compute the baud rate.
16–19
CSSCK[0:3]
PCS to SCK Delay Scaler
The CSSCK field selects the scaler value for the PCS to SCK delay. This field is only used in
Master Mode. The PCS to SCK delay is the delay between the assertion of PCS and the first
edge of the SCK. Table 211 lists the scaler values. The PCS to SCK delay is a multiple of the
system clock period and it is computed according to the following equation:
Equation 17
See Section , “CS to SCK delay (t
CSC
) for more details.
20–23
ASC[0:3]
After SCK Delay Scaler
The ASC field selects the scaler value for the After SCK delay. This field is only used in Master
Mode. The After SCK delay is the delay between the last edge of SCK and the negation of PCS.
Tabl e 212 lists the scaler values. The After SCK delay is a multiple of the system clock period,
and it is computed according to the following equation:
Equation 18
See Section , “After SCK delay (t
ASC
) for more details.
24–27
DT[0:3]
Delay after Transfer Scaler
The DT field selects the delay after transfer scaler. This field is only used in Master Mode. The
delay after transfer is the time between the negation of the PCS signal at the end of a frame and
the assertion of PCS at the beginning of the next frame. Table 213 lists the scaler values. In
continuous serial communications clock operation, the DT value is fixed to one TSCK. The delay
after transfer is a multiple of the system clock period and it is computed according to the
following equation:
Equation 19
See Section , “Delay after transfer (tDT) for more details.
Table 208. DSPIx_CTARn field descriptions (continued)
Field Descriptions
PBR Baud rate prescaler value
00 2
01 3
10 5
11 7
t
CSC
1
f
SYS
----------- PCSSCK CSSCK=
t
ASC
1
f
SYS
----------- PASC ASC=
t
DT
1
f
SYS
----------- PDT DT=