XC908AS60ACFU Motorola Semiconductor Products, XC908AS60ACFU Datasheet - Page 309

• Manufacturer Part Number: XC908AS60ACFU
• Description: MC68HC908AZ60A, MC68HC908AS60A Hcmos Microcontroller Unit Technical Data
• Manufacturer: Motorola Semiconductor Products

19.13.5 V
19.14 I/O Registers
MC68HC908AZ60A — Rev 2.0
MOTOROLA
SS
(Clock Ground)
The CPU can always read the state of the SS pin by configuring the
appropriate pin as an input and reading the data register. (See
5).
V
for the port output buffers. To reduce the ground return path loop and
minimize radio frequency (RF) emissions, connect the ground pin of the
slave to the V
Three registers control and monitor SPI operation:
X = don’t care
SPE SPMSTR MODFEN
SS
0
1
1
1
•
•
•
is the ground return for the serial clock pin, SPSCK, and the ground
SPI control register (SPCR $0010)
SPI status and control register (SPSCR $0011)
SPI data register (SPDR $0012)
X
0
1
1
Serial Peripheral Interface (SPI)
SS
pin.
X
X
0
1
Table 19-5. SPI Configuration
Master without MODF
SPI Configuration
Master with MODF
Not Enabled
Slave
Serial Peripheral Interface (SPI)
General-Purpose I/O;
General-Purpose I/O;
State of SS Logic
SS Ignored by SPI
SS Ignored by SPI
Input-Only to SPI
Input-Only to SPI
Technical Data
I/O Registers
Table 19-
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