mc9s08qg8 Freescale Semiconductor, Inc, mc9s08qg8 Datasheet - Page 218

• Manufacturer Part Number: mc9s08qg8
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Serial Peripheral Interface (S08SPIV3)
15.3.2
This read/write register is used to control optional features of the SPI system. Bits 7, 6, 5, and 2 are not
implemented and always read 0.
218
MODFEN
BIDIROE
Reset
LSBFE
SSOE
Field
Field
1
0
4
3
W
R
SPI Control Register 2 (SPIC2)
Slave Select Output Enable — This bit is used in combination with the mode fault enable (MODFEN) bit in
SPIC2 and the master/slave (MSTR) control bit to determine the function of the SS pin as shown in
LSB First (Shifter Direction)
0 SPI serial data transfers start with most significant bit
1 SPI serial data transfers start with least significant bit
Master Mode-Fault Function Enable — When the SPI is configured for slave mode, this bit has no meaning or
effect. (The SS pin is the slave select input.) In master mode, this bit determines how the SS pin is used (refer
to
0 Mode fault function disabled, master SS pin reverts to general-purpose I/O not controlled by SPI
1 Mode fault function enabled, master SS pin acts as the mode fault input or the slave select output
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 MOSI (MOMI) or MISO
(SISO) pin, respectively, as the single SPI data I/O pin. When SPC0 = 0, BIDIROE has no meaning or effect.
0 Output driver disabled so SPI data I/O pin acts as an input
1 SPI I/O pin enabled as an output
MODFEN
0
0
7
Table 15-2
0
0
1
1
= Unimplemented or Reserved
for more details).
0
0
6
SSOE
Table 15-1. SPIC1 Field Descriptions (continued)
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 1.01
0
1
0
1
Table 15-3. SPIC2 Register Field Descriptions
Figure 15-6. SPI Control Register 2 (SPIC2)
General-purpose I/O (not SPI)
General-purpose I/O (not SPI)
SS input for mode fault
Automatic SS output
0
0
5
Table 15-2. SS Pin Function
MODFEN
Master Mode
0
4
Description
Description
BIDIROE
3
0
Slave select input
Slave select input
Slave select input
Slave select input
0
0
2
Slave Mode
SPISWAI
Freescale Semiconductor
0
1
Table
SPC0
0
0
15-2.