MC68HC908LJ24 Datasheet, PDF (290/464 Pages) Motorola, Inc – Microcontrollers

Serial Peripheral Interface Module (SPI)
14.5 Functional Description
Figure 14-2 shows the structure of the SPI module.
INTERNAL BUS
CGMOUT ÷ 2
FROM SIM
÷2
CLOCK ^{÷ 8}
DIVIDER _{÷ 32}
÷ 128
TRANSMIT DATA REGISTER
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
RESERVED
TRANSMITTER CPU INTERRUPT REQUEST
RESERVED
RECEIVER/ERROR CPU INTERRUPT REQUEST
SPI
CONTROL
MODFEN
ERRIE
SPTIE
SPRIE
R
SPE
SPRF
SPTE
OVRF
MODF
SPWOM
Figure 14-2. SPI Module Block Diagram
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.
Data Sheet
290
MC68HC908LJ24/LK24 — Rev. 2.1
Serial Peripheral Interface Module (SPI)
Freescale Semiconductor