MC9S08GB60 Datasheet, PDF (197/290 Pages) Motorola, Inc – Microcontrollers

SPI Registers and Control Bits
12.4.1 SPI Control Register 1 (SPI1C1)
This read/write register includes the SPI enable control, interrupt enables, and configuration options.
Read:
Write:
Reset:
Bit 7
6
5
4
3
2
SPIE SPE SPTIE MSTR CPOL CPHA
0
0
0
0
0
1
Figure 12-7. SPI Control Register 1 (SPI1C1)
1
SSOE
0
Bit 0
LSBFE
0
SPIE — SPI Interrupt Enable (for SPRF and MODF)
This is the interrupt enable for SPI receive buffer full (SPRF) and mode fault (MODF) events.
1 = When SPRF or MODF is 1, request a hardware interrupt.
0 = Interrupts from SPRF and MODF inhibited (use polling).
SPE — SPI System Enable
Disabling the SPI halts any transfer that is in progress, clears data buffers, and initializes internal state
machines. SPRF is cleared and SPTEF is set to indicate the SPI transmit data buffer is empty.
1 = SPI system enabled.
0 = SPI system inactive.
SPTIE — SPI Transmit Interrupt Enable
This is the interrupt enable bit for SPI transmit buffer empty (SPTEF).
1 = When SPTEF is 1, hardware interrupt requested.
0 = Interrupts from SPTEF inhibited (use polling).
MSTR — Master/Slave Mode Select
1 = SPI module configured as a master SPI device.
0 = SPI module configured as a slave SPI device.
CPOL — Clock Polarity
This bit effectively places an inverter in series with the clock signal from a master SPI or to a slave SPI
device. Refer to Section 12.3.1, “SPI Clock Formats,” for more details.
1 = Active-low SPI clock (idles high).
0 = Active-high SPI clock (idles low).
CPHA — Clock Phase
This bit selects one of two clock formats for different kinds of synchronous serial peripheral devices.
Refer to Section 12.3.1, “SPI Clock Formats,” for more details.
1 = First edge on SPSCK occurs at the start of the first cycle of an 8-cycle data transfer.
0 = First edge on SPSCK occurs at the middle of the first cycle of an 8-cycle data transfer.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor
197