MC68HC11F1 Datasheet, PDF (49/68 Pages) Motorola, Inc – Technical Summary 8-Bit Microcontroller

10 Serial Peripheral Interface
The serial peripheral interface (SPI) allows the MCU to communicate synchronously with peripheral de-
vices and other microprocessors. The SPI protocol facilitates rapid exchange of serial data between de-
vices in a control system. The MC68HC11F1 and MC68HC11FC0 can be set up for master or slave
operation. Standard data rates can be as high as one half of the E-clock rate when configured as mas-
ter, and as fast as the E-clock when configured as slave.
The MC68HC11FC0 has an additional control bit that allows the SPI baud rate counter to be bypassed.
This allows a master mode baud rate equal to the E-clock frequency.
10.1 SPI Block Diagram
DOTTED LINE CONNECTIONS
PRESENT ON MC68HC11FC0 ONLY
SPIE
SPE
DWOM
MSTR
CPHA
CPOL
SPR1
SPR0
SPI STATUS REGISTER
SPIE
SPE
SPI
CONTROL
MSTR
SPI INTERRUPT
REQUEST
INTERNAL
MCU CLOCK
÷2
SPR0
SPR1
÷4
÷16
÷32
CLOCK LOGIC
SPRBYP
MSB
LSB
8-BIT SHIFT REGISTER
READ DATA BUFFER
SS
PD5
M
SCK
S
PD4
S
MOSI
M
PD3
M
MISO
S
PD2
MC68HC11F1/FC0
MC68HC11FTS/D
Figure 12 SPI Block Diagram
MOTOROLA
49