mc68hc908mr24 Freescale Semiconductor, Inc, mc68hc908mr24 Datasheet - Page 279

• Manufacturer Part Number: mc68hc908mr24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

13.12.5 V
13.13 I/O Registers
13.13.1 SPI Control Register
MC68HC908MR24 — Rev. 4.1
Freescale Semiconductor
SS
(Clock Ground)
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:
The SPI control register (SPCR):
1. X = don’t care
SPE
SS
•
•
•
•
•
•
•
•
•
0
1
1
1
is the ground return for the serial clock pin, SPSCK, and the ground
SPI control register, SPCR
SPI status and control register, SPSCR
SPI data register, SPDR
Enables SPI module interrupt requests
Selects CPU interrupt requests or DMA service requests
Configures the SPI module as master or slave
Selects serial clock polarity and phase
Configures the SPSCK, MOSI, and MISO pins as open-drain
outputs
Enables the SPI module
Serial Peripheral Interface Module (SPI)
SPMSTR
X
0
1
1
(1)
SS
pin of the master.
MODFEN
Table 13-3. SPI Configuration
X
X
0
1
SPI Configuration
Master with MODF
without MODF
Not Enabled
Master
Slave
Serial Peripheral Interface Module (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
Advance Information
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