Chapter 20 Deserial Serial Peripheral Interface (DSPI)
MPC5602P Microcontroller Reference Manual, Rev. 4
448
Freescale Semiconductor
Address: Base + 0x000C (DSPI
x
_CTAR0)
Base + 0x0010 (DSPI
x
_CTAR1)
Base + 0x0014 (DSPI
x
_CTAR2)
Base + 0x0018 (DSPI
x
_CTAR3)
Base + 0x001C (DSPIx_CTAR4)
Base + 0x0020 (DSPI
x
_CTAR5)
Base + 0x0024 (DSPI
x
_CTAR6)
Base + 0x0028 (DSPI
x
_CTAR7)
Access: User read/write
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R
DBR
FMSZ
CPOL
CPHA
LSB
FE
PCSSCK
PASC
PDT
PBR
W
Reset
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
R
CSSCK
ASC
DT
BR
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 20-5. DSPI Clock and Transfer Attributes Registers 0–7 (DSPI
x
_CTARn)
Table 20-5. DSPI
x
_CTARn
field descriptions
Field
Descriptions
0
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 in
. See the BR[0:3] field
description 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 neither the Continuous SCK Enable or the Modified
Timing Format Enable bits should be set.
0 The baud rate is computed normally with a 50/50 duty cycle.
1 The baud rate is doubled with the duty cycle depending on the baud rate prescaler.
1–4
FMSZ[0:3]
Frame Size
The FMSZ field selects the number of bits transferred per frame. The FMSZ field is used in Master
Mode and Slave Mode.
lists the frame size encodings.
5
CPOL
Clock Polarity
The CPOL bit selects the inactive state of the Serial Communications Clock (SCK). This bit is
used in both Master and Slave Mode. For successful communication between serial devices, the
devices must have identical clock polarities. When the Continuous Selection Format is selected,
switching between clock polarities without stopping the DSPI can cause errors in the transfer due
to the peripheral device interpreting the switch of clock polarity as a valid clock edge.
0 The inactive state value of SCK is low.
1 The inactive state value of SCK is high.
6
CPHA
Clock Phase
The CPHA bit selects which edge of SCK causes data to change and which edge causes data to
be captured. This bit is used in both Master and Slave Mode. For successful communication
between serial devices, the devices must have identical clock phase settings. Continuous SCK
is only supported for CPHA = 1.
0 Data is captured on the leading edge of SCK and changed on the following edge.
1 Data is changed on the leading edge of SCK and captured on the following edge.