mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 430

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

8-Bit Serial Peripheral Interface (SPIV3)
19.1.3
As shown in
prescale bits (SPI1BR[SPPR]) choose a prescale divisor of 1, 2, 3, 4, 5, 6, 7, or 8. The three rate select bits
(SPI1BR[SPR]) divide the output of the prescaler stage by 2, 4, 8, 16, 32, 64, 128, or 256 to obtain the
internal SPI master mode bit-rate clock.
19-4
Bus Rate
Clock
SPI System
LSBFE
MSTR
Enable
SPE
SPI Baud Rate Generation
Figure
Clock Generator
SPI1
Master/Slave
Mode Select
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
19-3, the clock source for the SPI baud rate generator is the bus clock. The three
BR
Shift
Out
Shift
Direction
Mode Fault
Tx Buffer (Write
Rx Buffer (Read
Detection
Clock
Logic
SPI Shift Register
Clock
Figure 19-2. SPI Module Block Diagram
Shift
MODF
Rx Buffer
SPRF
SPI1
SPI1
Full
D)
D)
Tx Buffer
Empty
SPTEF
SPTIE
SPIE
Shift
In
Master Clock
MODFEN
Slave Clock
BIDIRO
SPC0
SSOE
M
S
M
S
M
S
Master/
Slave
Pin Control
Freescale Semiconductor
SPI
Interrupt
Request
MOSI
(MOMI)
MISO
(SISO)
SPSCK
SS