Deserial Serial Peripheral Interface (DSPI)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
Freescale Semiconductor
23-11
Preliminary
Table 23-4. DSPI_CTARn Field Description
Field
Description
DBR
Double Baud Rate. The DBR bit doubles the effective baud rate of the serial communications clock (SCK). This
field is only used in master mode. It effectively halves the baud rate division ratio supporting faster frequencies
and odd division ratios for the serial communications clock (SCK). When the DBR bit is set, the duty cycle of the
serial communications clock (SCK) depends on the value in the baud rate prescaler and the clock phase bit as
listed below. See the BR field below and
Section 23.4.7.1, “Baud Rate Generator
,” for details on how to compute
the baud rate. If the overall baud rate is divide by two or divide by three of the system clock then the continuous
SCK enable or the modified timing format enable bits must not be set.
0 The baud rate is computed normally with a 50/50 duty cycle
1 Baud rate is doubled with the duty cycle depending on the baud rate prescaler
FMSZ
FMSZ. Selects the number of bits transferred per frame. The FMSZ field is used in master mode and slave mode.
The table below lists the frame sizes.
DBR
CPHA
PBR
SCK Duty Cycle
0
any
any
50/50
1
0
00
50/50
1
0
01
33/66
1
0
10
40/60
1
0
11
43/57
1
1
00
50/50
1
1
01
66/33
1
1
10
60/40
1
1
11
57/43
FMSZ
Framesize
FMSZ
Framesize
0000
Reserved
1000
9
0001
Reserved
1001
10
0010
Reserved
1010
11
0011
4
1011
12
0100
5
1100
13
0101
6
1101
14
0110
7
1110
15
0111
8
1111
16