MC9S08RC8 Datasheet, PDF (174/234 Pages) Freescale Semiconductor, Inc – Microcontrollers

Serial Peripheral Interface (SPI) Module
BIDIROE — Bidirectional Mode Output Enable
When bidirectional mode is enabled by SPI pin control 0 (SPC0) = 1, BIDIROE determines whether
the SPI data output driver is enabled to the single bidirectional SPI I/O pin. Depending on whether the
SPI is configured as a master or a slave, it uses either the MOSI1 (MOMI) or MISO1 (SISO) pin,
respectively, as the single SPI data I/O pin. When SPC0 = 0, BIDIROE has no meaning or effect.
1 = SPI I/O pin enabled as an output.
0 = Output driver disabled so SPI data I/O pin acts as an input.
SPISWAI — SPI Stop in Wait Mode
1 = SPI clocks stop when the MCU enters wait mode.
0 = SPI clocks continue to operate in wait mode.
SPC0 — SPI Pin Control 0
The SPC0 bit chooses single-wire bidirectional mode. If MSTR = 0 (slave mode), the SPI uses the
MISO1 (SISO) pin for bidirectional SPI data transfers. If MSTR = 1 (master mode), the SPI uses the
MOSI1 (MOMI) pin for bidirectional SPI data transfers. When SPC0 = 1, BIDIROE is used to enable
or disable the output driver for the single bidirectional SPI I/O pin.
1 = SPI configured for single-wire bidirectional operation.
0 = SPI uses separate pins for data input and data output.
13.4.3 SPI Baud Rate Register (SPI1BR)
This register is used to set the prescaler and bit rate divisor for an SPI master. This register may be read or
written at any time.
Read:
Write:
Reset:
Bit 7
6
5
4
3
2
1
Bit 0
0
<st-blue> <st-blue> <st-blue>
0
<st-blue> <st-blue> <st-blue>
SPPR2 SPPR1 SPPR0
SPR2 SPR1 SPR0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 13-9. SPI Baud Rate Register (SPI1BR)
SPPR2:SPPR1:SPPR0 — SPI Baud Rate Prescale Divisor
This 3-bit field selects one of eight divisors for the SPI baud rate prescaler as shown in Table 13-2. The
input to this prescaler is the bus rate clock (BUSCLK). The output of this prescaler drives the input of
the SPI baud rate divider (see Figure 13-4).
MC9S08RC/RD/RE/RG Data Sheet, Rev. 1.11
174
Freescale Semiconductor