MC68HC08AZ0 Datasheet, PDF (228/444 Pages) Motorola, Inc – Advance Information

Freescale Semiconductor, Inc.
Serial Peripheral Interface Module (SPI)
high or must be reconfigured as general purpose I/O not affecting the
SPI. See Mode fault error on page 232. When CPHA = ‘0’, the first
SPSCK edge is the MSB capture strobe. Therefore the slave must begin
driving its data before the first SPSCK edge, and a falling edge on the
SS pin is used to start the transmission. The SS pin must be toggled high
and then low between each byte transmitted.
SCK CYCLE #
(FOR REFERENCE)
SCK (CPOL =’0’)
SCK (CPOL =1)
MOSI
(FROM MASTER)
MISO
(FROM SLAVE)
SS (TO SLAVE)
CAPTURE STROBE
1
2
3
4
5
6
7
8
MSB
BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1
LSB
MSB
BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1
LSB
Figure 4. Transmission format (CPHA = ‘0’)
MISO/MOSI
MASTER SS
SLAVE SS
(CPHA =’0’)
SLAVE SS
(CPHA = 1)
BYTE 1
BYTE 2
BYTE 3
Figure 5. CPHA/SS timing
MC68HC08AZ0
226
Serial Peripheral Interface Module (SPI)
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