mc9s12xd256 Freescale Semiconductor, Inc, mc9s12xd256 Datasheet - Page 522

• Manufacturer Part Number: mc9s12xd256
• Description: Hcs12x Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 12 Serial Peripheral Interface (S12SPIV4)
12.3.2.3
Read: Anytime
Write: Anytime; writes to the reserved bits have no effect
The baud rate divisor equation is as follows:
The baud rate can be calculated with the following equation:
522
SPPR[2:0]
SPR[2:0]
Reset
Field
6–4
2–0
W
R
SPI Baud Rate Preselection Bits — These bits specify the SPI baud rates as shown in
mode, a change of these bits will abort a transmission in progress and force the SPI system into idle state.
SPI Baud Rate Selection Bits — These bits specify the SPI baud rates as shown in
a change of these bits will abort a transmission in progress and force the SPI system into idle state.
Bidirectional
Bidirectional
SPI Baud Rate Register (SPIBR)
0
0
7
Pin Mode
For maximum allowed baud rates, please refer to the SPI Electrical
Specification in the Electricals chapter of this data sheet.
Normal
Normal
= Unimplemented or Reserved
SPPR2
0
6
SPC0
Baud Rate = BusClock / BaudRateDivisor
BaudRateDivisor = (SPPR + 1) 2
0
1
0
1
Figure 12-5. SPI Baud Rate Register (SPIBR)
Table 12-4. Bidirectional Pin Configurations
Table 12-5. SPIBR Field Descriptions
BIDIROE
SPPR1
MC9S12XDP512 Data Sheet, Rev. 2.17
0
5
X
0
1
X
0
1
Master Mode of Operation
Slave Mode of Operation
MISO not used by SPI
SPPR0
NOTE
0
4
Slave Out
Master In
Slave I/O
Slave In
Description
MISO
(SPR + 1)
0
0
3
MOSI not used by SPI
SPR2
0
2
Master Out
Master I/O
Master In
Slave In
MOSI
Table
Freescale Semiconductor
SPR1
12-6. In master mode,
Table
0
1
12-6. In master
Eqn. 12-1
Eqn. 12-2
SPR0
0
0