mc9s08gt16a Freescale Semiconductor, Inc, mc9s08gt16a Datasheet - Page 191

• Manufacturer Part Number: mc9s08gt16a
• Description: Hcs08 Microcontrollers 8-bit Microcontroller Family
• Manufacturer: Freescale Semiconductor, Inc

When the SPI is configured as a master, the clock output is routed to the SPSCK pin, the shifter output is
routed to MOSI, and the shifter input is routed from the MISO pin.
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.
12.1.3
As shown in
prescale bits (SPPR2:SPPR1:SPPR0) choose a prescale divisor of 1, 2, 3, 4, 5, 6, 7, or 8. The three rate
select bits (SPR2:SPR1:SPR0) divide the output of the prescaler stage by 2, 4, 8, 16, 32, 64, 128, or 256
to get the internal SPI master mode bit-rate clock.
Freescale Semiconductor
BUS RATE
CLOCK
SPI SYSTEM
ENABLE
LSBFE
MSTR
SPE
SPI Baud Rate Generation
CLOCK GENERATOR
Figure
SPIBR
MASTER/SLAVE
MODE SELECT
12-5, the clock source for the SPI baud rate generator is the bus clock. The three
SHIFT
OUT
SHIFT
DIRECTION
Tx BUFFER (WRITE SPID)
Rx BUFFER (READ SPID)
MODE FAULT
DETECTION
SPI SHIFT REGISTER
CLOCK
CLOCK
LOGIC
Figure 12-4. SPI Module Block Diagram
SHIFT
MC9S08GT16A/GT8A Data Sheet, Rev. 1
MODF
Rx BUFFER
SPRF
FULL
Tx BUFFER
EMPTY
SHIFT
SPTEF
SPTIE
SPIE
IN
MASTER CLOCK
SLAVE CLOCK
BIDIROE
MODFEN
SPC0
SSOE
Serial Peripheral Interface (S08SPIV3)
PIN CONTROL
M
S
M
S
M
S
MASTER/
SLAVE
SPI
INTERRUPT
REQUEST
MOSI
(MOMI)
MISO
(SISO)
SPSCK
SS
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