mc68hc908gp20 Freescale Semiconductor, Inc, mc68hc908gp20 Datasheet - Page 317

• Manufacturer Part Number: mc68hc908gp20
• Description: M68hc08 Family Of 8-bit Microcontroller Units Mcus
• Manufacturer: Freescale Semiconductor, Inc

20.5.1 Master Mode
MC68HC908GP20
Freescale Semiconductor
NOTE:
—
Rev 2.1
If a port bit is configured for input, then an internal pullup device may be
enabled for that port bit. (See
Register.)
The following paragraphs describe the operation of the SPI module.
The SPI operates in master mode when the SPI master bit, SPMSTR, is
set.
Configure the SPI modules as master or slave before enabling them.
Enable the master SPI before enabling the slave SPI. Disable the slave
SPI before disabling the master SPI. (See
Register.)
Only a master SPI module can initiate transmissions. Software begins
the transmission from a master SPI module by writing to the transmit
data register. If the shift register is empty, the byte immediately transfers
to the shift register, setting the SPI transmitter empty bit, SPTE. The byte
begins shifting out on the MOSI pin under the control of the serial clock.
(See
SHIFT REGISTER
Figure
GENERATOR
MASTER MCU
BAUD RATE
Figure 20-3. Full-Duplex Master-Slave Connections
20-3.)
MISO
MOSI
SPSCK
SS
16.5.3 Port C Input Pullup Enable
V
DD
20.14.1 SPI Control
SPSCK
MISO
MOSI
SS
Advance Information
SHIFT REGISTER
SLAVE MCU
317