s908az32ag2cfue Freescale Semiconductor, Inc, s908az32ag2cfue Datasheet - Page 181

• Manufacturer Part Number: s908az32ag2cfue
• Description: M68hc08 Microcontrollers 8-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

17.12.5 V
V
reduce the ground return path loop and minimize radio frequency (RF) emissions, connect the ground pin
of the slave to the V
17.13 I/O Registers
Three registers control and monitor SPI operation:
17.13.1 SPI Control Register
The SPI control register:
SPRIE — SPI Receiver Interrupt Enable Bit
SPMSTR — SPI Master Bit
CPOL — Clock Polarity Bit
Freescale Semiconductor
SS
•
•
•
•
•
•
•
•
•
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
17-4
CPOL bits. Reset clears the CPOL bit.
is the ground return for the serial clock pin, SPSCK, and the ground for the port output buffers. To
1 = SPRF CPU interrupt requests enabled
0 = SPRF CPU interrupt requests disabled
1 = Master mode
0 = Slave mode
SPI control register (SPCR $0010)
SPI status and control register (SPSCR $0011)
SPI data register (SPDR $0012)
Enables SPI module interrupt requests
Selects CPU 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
SS
Figure
Address:
(Clock Ground)
Reset:
Read:
Write:
17-5.) To transmit data between SPI modules, the SPI modules must have identical
SS
pin.
SPRIE
$0010
Bit 7
R
0
Figure 17-12. SPI Control Register (SPCR)
= Reserved
R
6
0
MC68HC908AZ32A Data Sheet, Rev. 2
SPMSTR
5
1
CPOL
4
0
CPHA
3
1
SPWOM
2
0
SPE
1
0
SPTIE
Bit 0
0
I/O Registers
Figure
181