MC68HC711KS2MFN4 Freescale Semiconductor, MC68HC711KS2MFN4 Datasheet - Page 171

• Manufacturer Part Number: MC68HC711KS2MFN4
• Description: 32K EPROM - SLOW MODE
• Manufacturer: Freescale Semiconductor

8.4.4 Slave Select (SS)
8.4.5 SPI Timing
M68HC11K Family
MOTOROLA
(CPHA = 0) DATA OUT
(CPHA = 1) DATA OUT
FOR REFERENCE
SCK (CPOL = 0)
SCK (CPOL = 1)
SAMPLE INPUT
SAMPLE INPUT
SS (TO SLAVE)
SCK CYCLE #
The slave select (SS) input is used to target specific devices in the SPI
system. It must be pulled low on a targeted slave device prior to any
communication with a master and must remain low for the duration of the
transaction. SS must always be high on any device in master mode.
Pulling SS low on a master mode device generates a mode fault error
(see
Four possible timing relationships are available through control bits
CPOL (clock polarity) and CPHA (clock phase) in the SPCR. These bits
must be the same in both master and slave devices. The master device
always places data on the MOSI line approximately a half-cycle before
the SCK clock edge. This enables the slave device to latch the data. See
Figure
A write collision is normally a slave error because a slave has no control
over when a master initiates a transfer. A master knows when a transfer
is in progress, so there is no reason for a master to generate a
write-collision error, although the SPI logic can detect write collisions in
both master and slave devices.
MSB
Figure 8-2. Data Clock Timing Diagram
8.5.1 Mode Fault
MSB
1
8-2.
6
Serial Peripheral Interface (SPI)
2
6
5
3
5
4
Error).
4
4
3
5
3
2
6
2
1
Serial Peripheral Interface (SPI)
7
1
LSB
SPI Signal Descriptions
LSB
8
Technical Data
171