MC68HC711K4CFN4 Datasheet, PDF (56/80 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 ÷8 ÷16 ÷64 ÷128
MSB
LSB
8-BIT SHIFT REGISTER
READ DATA BUFFER
SELECT
SPI CLOCK (MASTER)
CLOCK
CLOCK
LOGIC
S
M
M
S
PIN
CONTROL
LOGIC
S
M
MISO/
PD2
MOSI/
PD3
SCK/
PD4
SS/
PD5
OPTIONS REGISTER 2
SPI CONTROL
MSTR
SPE
SPIE
SPSR SPI STATUS REGISTER
SPCR SPI CONTROL REGISTER
8
8
8
SPI INTERRUPT
REQUEST
INTERNAL
DATA BUS
Figure 12 SPI Block Diagram
MOTOROLA
56
M68HC11 K Series
MC68HC11KTS/D