MC908QY8CDWE Datasheet, PDF (159/232 Pages) Freescale Semiconductor, Inc – Addendum to MC68HC908QB8, rev. 3

Functional Description
15.3 Functional Description
The SPI module allows full-duplex, synchronous, serial communication between the MCU and peripheral
devices, including other MCUs. Software can poll the SPI status flags or SPI operation can be interrupt
driven.
The following paragraphs describe the operation of the SPI module.
INTERNAL BUS
TRANSMIT DATA REGISTER
BUSCLK
÷2
CLOCK ^{÷ 8}
DIVIDER _{÷ 32}
÷ 128
SHIFT REGISTER
76543210
RECEIVE DATA REGISTER
SPMSTR SPE
CLOCK
SELECT
SPR1 SPR0
CLOCK
LOGIC
PIN
CONTROL
LOGIC
M
S
SPMSTR CPHA CPOL
MISO
MOSI
SPSCK
SS
TRANSMITTER INTERRUPT REQUEST
RECEIVER/ERROR INTERRUPT REQUEST
SPI
CONTROL
MODFEN
ERRIE
SPTIE
SPRIE
SPE
SPWOM
SPRF
SPTE
OVRF
MODF
Figure 15-2. SPI Module Block Diagram
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
157