mc68hc908gr8vp Freescale Semiconductor, Inc, mc68hc908gr8vp Datasheet - Page 221

• Manufacturer Part Number: mc68hc908gr8vp
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

20.13 I/O Registers
Three registers control and monitor SPI operation:
20.13.1 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
•
•
•
•
•
•
•
•
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
Figure 20-4
identical CPOL values. Reset clears the CPOL bit.
This read/write bit controls the timing relationship between the serial clock and SPI data. (See
Figure 20-4
identical CPHA values. When CPHA = 0, the SS pin of the slave SPI module must be set to logic 1
between bytes. See
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
Address: $0010
and
and
Reset:
Read:
Write:
Figure
Figure
SPRIE
Figure
Bit 7
R
0
20-6.) To transmit data between SPI modules, the SPI modules must have
20-6.) To transmit data between SPI modules, the SPI modules must have
MC68HC908GR8 • MC68HC908GR4 Data Sheet, Rev. 7
Figure 20-13. SPI Control Register (SPCR)
= Reserved
20-12. Reset sets the CPHA bit.
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
221