MC68HC812A4 Datasheet, PDF (275/342 Pages) Motorola, Inc – 16-bit device composed of standard on-chip peripheral modules connected by an intermodule bus. Modules include

Serial Peripheral Interface (SPI)
SPI Register Descriptions and Reset Initialization
15.7.2 SPI Control Register 2
Address: $00D1
Bit 7
6
5
4
3
2
1
Bit 0
Read: 0
0
0
0
0
PUPS RDS
SPC0
Write:
Reset: 0
0
0
0
1
0
0
0
= Unimplemented
Figure 15-10. SPI Control Register 2 (SP0CR2)
Read: Anytime
Write: Anytime
PUPS — Pullup Port S Bit
Setting PUPS enables internal pullup devices on all port S input pins.
If a pin is programmed as output, the pullup device becomes inactive.
1 = Pullups enabled
0 = Pullups disabled
RDS — Reduced Drive Port S Bit
Setting RDS lowers the drive capability of all port S output pins for
lower power consumption and less noise.
1 = Reduced drive
0 = Normal drive
SPC0 — Serial Pin Control Bit 0
SPC0 enables single-wire operation of the MOSI and MISO pins.
Table 15-2. Single-Wire Operation
Control Bits
Pins
SPC0 MSTR DDRS5 DDRS4
MOSI
MISO
1
0
1
—
Master input
Master output
General-purpose I/O
1
0
—
0
1
General-purpose I/O
Slave input
Slave output
Advance Information
MOTOROLA
Serial Peripheral Interface (SPI)
MC68HC812A4 — Rev. 3.0
275