XC908AS60ACFU Motorola Semiconductor Products, XC908AS60ACFU Datasheet - Page 290

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

Serial Peripheral Interface (SPI)
19.5.1 Master Mode
Technical Data
290
NOTE:
SHIFT REGISTER
GENERATOR
BAUD RATE
MASTER MCU
Figure 19-2. Full-Duplex Master-Slave Connections
The SPI operates in master mode when the SPI master bit, SPMSTR
(SPCR $0010), is set.
Configure the SPI modules as master and slave before enabling them.
Enable the master SPI before enabling the slave SPI. Disable the slave
SPI before disabling the master SPI. See
310.
Only a master SPI module can initiate transmissions. Software begins
the transmission from a master SPI module by writing to the SPI data
register. If the shift register is empty, the byte immediately transfers to
the shift register, setting the SPI transmitter empty bit, SPTE (SPSCR
$0011). The byte begins shifting out on the MOSI pin under the control
of the serial clock. (See
The SPR1 and SPR0 bits control the baud rate generator and determine
the speed of the shift register. (See
on page 312). Through the SPSCK pin, the baud rate generator of the
master also controls the shift register of the slave peripheral.
MISO
MOSI
SPSCK
SS
Serial Peripheral Interface (SPI)
V
Table
DD
19-4).
SPSCK
MISO
MOSI
SPI Status and Control Register
SS
SPI Control Register
MC68HC908AZ60A — Rev 2.0
SHIFT REGISTER
SLAVE MCU
MOTOROLA
on page