Datasheet

Serial Peripheral Interface (S08SPIV3)
MC9S08GT16A/GT8A Data Sheet, Rev. 1
202 Freescale Semiconductor
12.6.1.2 Pseudo—Code Example
In this example, the SPI module will be set up for master mode with only transmit interrupts enabled to
run at a maximum baud rate of bus clock divided by 2. Clock phase and polarity will be set for an
active-high SPI clock where the first edge on SPSCK occurs at the start of the first cycle of a data transfer.
SPIC1 = 0x74(%01110100)
Bit 7 SPIE = 0 Disables receive and mode fault interrupts
Bit 6 SPE = 1 Enables the SPI system
Bit 5 SPTIE = 1 Enables SPI transmit interrupts
Bit 4 MSTR = 1 Sets the SPI module as a master SPI device
Bit 3 CPOL = 0 Configures SPI clock as active-high
Bit 2 CPHA = 1 First edge on SPSCK at start of first data transfer cycle
Bit 1 SSOE = 0 Determines
SS pin function when mode fault enabled
Bit 0 LSBFE = 0 SPI serial data transfers start with most significant bit
SPIC2 = 0x00(%00000000)
Bit 7:5 = 000 Unimplemented
Bit 4 MODFEN = 0 Disables mode fault function
Bit 3 BIDIROE = 0 SPI data I/O pin acts as input
Bit 2 = 0 Unimplemented
Bit 1 SPISWAI = 0 SPI clocks operate in wait mode
Bit 0 SPC0 = 0 SPI uses separate pins for data input and output
SPIBR = 0x00(%00000000)
Bit 7 = 0 Unimplemented
Bit 6:4 = 000 Sets prescale divisor to 1
Bit 3 = 0 Unimplemented
Bit 2:0 = 000 Sets baud rate divisor to 2
SPIS = 0x00(%00000000)
Bit 7 SPRF = 0 Flag is set when receive data buffer is full
Bit 6 = 0 Unimplemented
Bit 5 SPTEF = 0 Flag is set when transmit data buffer is empty
Bit 4 MODF = 0 Mode fault flag for master mode
Bit 3:0 = 0 Unimplemented
SPID = 0xxx
Holds data to be transmitted by transmit buffer and data received by receive buffer.