MC68HC705E5 Datasheet, PDF (99/148 Pages) Freescale Semiconductor, Inc – General Release Specification

Freescale Semiconductor, Inc.
Synchronous Serial Interface (SSI)
SSI Signals
pin will depend on the value of the CPOL bit. Data can be sent or
received in either MSB first format (LSBF = 0) or LSB first format
(LSBF = 1).
If (CPOL = 1), the first falling edge of SCK will shift the first data bit
out to the SDIO pin. Subsequent falling edges of SCK will shift the
remaining data bits out.
If (CPOL = 0), the first data bit will be driven out to the SDIO pin before
the first rising edge of SCK. Subsequent falling edges of SCK will shift
the remaining data bits out.
SDIO as an Input Pin
The SDIO pin will accept data once the SSI is enabled and the SDIR
bit = 0. Valid data must be present at least 100 ns before the rising
edge of the clock and remain valid for 100 ns after the edge. See
Figure 12-2 and Figure 12-3.
SCK
SDIO
SE
BIT 1
BIT 2
BIT 3
BIT 7
BIT 8
Figure 12-2. Synchronous Serial Interface Timing (CPOL = 1)
SCK
SDIO
BIT 1
BIT 2
BIT 3
BIT 7
BIT 8
SE
Figure 12-3. Synchronous Serial Interface Timing (CPOL = 0)
MC68HC705E5 — Rev. 1.0
General Release Specification
Synchronous Serial Interface (SSI)
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