MC68HC11KA4TS Datasheet, PDF (44/68 Pages) Motorola, Inc – 8-Bit Microcontroller

8 Serial Peripheral Interface
The SPI allows the MCU to communicate synchronously with peripheral devices and other micropro-
cessors. Data rates can be as high as 2 Mbits per second when configured as a master and 4 Mbits per
second when configured as a slave (assuming 4 MHz bus speed).
Two control bits in OPT2 allow the transfer of data either MSB or LSB first and select an additional divide
by four stage to be inserted before the SPI baud rate clock divider.
INTERNAL
MCU CLOCK
DIVIDER
÷2 ÷4 ÷16 ÷32
S
M
MSB
LSB
M
8/16-BIT SHIFT REGISTER
S
READ DATA BUFFER
SELECT
SPI CLOCK (MASTER)
CLOCK
CLOCK
S
LOGIC
M
MISO
PD2
MOSI
PD3
SCK
PD4
SS
PD5
SPI CONTROL
MSTR
SPE
SPI STATUS REGISTER
8
8
SPI CONTROL REGISTER
8
SPI INTERRUPT
REQUEST
INTERNAL
DATA BUS
Figure 12 SPI Block Diagram
SPI BLOCK 2SPR
MOTOROLA
44
MC68HC11KA4
MC68HC11KA4TS/D