MC68HC908GT16_07 FREESCALE [Freescale Semiconductor, Inc], MC68HC908GT16_07 Datasheet - Page 213

• Manufacturer Part Number: MC68HC908GT16_07
• Description: Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

16.12 I/O Registers
Three registers control and monitor SPI operation:
16.12.1 SPI Control Register
The SPI control register:
SPRIE — SPI Receiver Interrupt Enable Bit
SPMSTR — SPI Master Bit
CPOL — Clock Polarity Bit
CPHA — Clock Phase Bit
Freescale Semiconductor
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This read/write bit enables CPU interrupt requests generated by the SPRF bit. The SPRF bit is set
when a byte transfers from the shift register to the receive data register. Reset clears the SPRIE bit.
This read/write bit selects master mode operation or slave mode operation. Reset sets the SPMSTR
bit.
This read/write bit determines the logic state of the SPSCK pin between transmissions. (See
16-5
CPOL values. Reset clears the CPOL bit.
This read/write bit controls the timing relationship between the serial clock and SPI data. (See
16-5
CPHA values. When CPHA = 0, the SS pin of the slave SPI module must be high between bytes. (See
Figure
1 = SPRF CPU interrupt requests enabled
0 = SPRF CPU interrupt requests disabled
1 = Master mode
0 = Slave mode
SPI control register (SPCR)
SPI status and control register (SPSCR)
SPI data register (SPDR)
Enables SPI module interrupt 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
and
and
16-13.) Reset sets the CPHA bit.
Figure
Figure
Address: $0010
Reset:
Read:
Write:
MC68HC908GT16 • MC68HC908GT8 • MC68HC08GT16 Data Sheet, Rev. 5.0
16-7.) To transmit data between SPI modules, the SPI modules must have identical
16-7.) To transmit data between SPI modules, the SPI modules must have identical
SPRIE
Bit 7
R
0
Figure 16-14. SPI Control Register (SPCR)
= Reserved
R
6
0
SPMSTR
5
1
CPOL
4
0
CPHA
3
1
SPWOM
2
0
SPE
1
0
SPTIE
Bit 0
0
I/O Registers
Figure
Figure
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