mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 444

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

BUS RATE
16-Bit Serial Peripheral Interface (SPI16)
When the SPI is configured as a slave, the SPSCK pin is routed to the clock input of the SPI, the shifter
output is routed to MISO, and the shifter input is routed from the MOSI pin.
In the external SPI system, simply connect all SPSCK pins to each other, all MISO pins together, and all
MOSI pins together. Peripheral devices often use slightly different names for these pins.
20.2
The SPI optionally shares four port pins. The function of these pins depends on the settings of SPI control
bits. When the SPI is disabled (SPE = 0), these four pins revert to being general-purpose port I/O pins that
are not controlled by the SPI.
20-4
CLOCK
FIFOMODE-
SPI SYSTEM
SPIMODE
ENABLE
LSBFE
MSTR
SPE
RNFULLF
RNFULLIEN
TNEAREF
CLOCK GENERATOR
TNEARIEN
External Signal Description
SPIBR
MASTER/SLAVE
MODE SELECT
SHIFT
OUT
8 OR 16
BIT MODE
SHIFT
DIRECTION
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
Tx BUFFER (WRITE SPIxDH:SPIxDL)
Rx BUFFER (READ SPIxDH:SPIxDL)
MODE FAULT
DETECTION
CLOCK
CLOCK
LOGIC
SHIFT
Rx FIFO (8byte deep)
Tx FIFO (8byte deep)
SPI SHIFT REGISTER
MODF
Figure 20-2. SPI Module Block Diagram
Rx BUFFER
SPRF
FULL
Tx BUFFER
EMPTY
SHIFT
SPTEF
SPTIE
SPIE
IN
MASTER CLOCK
SLAVE CLOCK
16-BIT COMPARATOR
BIDIROE
MODFEN
SPC0
SSOE
SPIxMH:SPIxML
16-BIT LATCH
PIN CONTROL
M
S
M
S
M
S
MASTER/
SLAVE
SPMF
SPMIE
Freescale Semiconductor
SPI
INTERRUPT
REQUEST
MOSI
(MOMI)
MISO
(SISO)
SPSCK
SS