Chapter 16 Serial Peripheral Interface (S12SPIV4)
MC9S12XDP512 Data Sheet, Rev. 2.11
712 Freescale Semiconductor

This is a high level description only, detailed descriptions of operating modes are contained in

Section 16.4.7, “Low Power Mode Options”.

16.1.3 Block Diagram

Figure 16-1 gives an overview on the SPI architecture. The main parts of the SPI are status, control and

data registers, shifter logic, baud rate generator, master/slave control logic, and port control logic.

Figure 16-1. SPI Block Diagram

SPI Control Register 1
SPI Control Register 2
SPI Baud Rate Register
SPI Status Register
SPI Data Register
Shifter
Port
Control
Logic
MOSI
SCK
Interrupt Control
SPI
MSB LSB
LSBFE=1 LSBFE=0
LSBFE=0 LSBFE=1
Data In
LSBFE=1
LSBFE=0
Data Out
8
8
Baud Rate Generator
Prescaler
Bus Clock
Counter
Clock Select
SPPR 33
SPR
Baud Rate
Phase +
Polarity
Control
Master
Slave
SCK In
SCK Out
Master Baud Rate
Slave Baud Rate
Phase +
Polarity
Control
Control
Control CPOL CPHA
2
BIDIROE
SPC0
2
Shift Sample
ClockClock
MODF
SPIF SPTEF
SPI
Request
Interrupt
SS