Deserial Serial Peripheral Interface (DSPI)
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 20-61
Figure 20-37 shows the modified transfer format for CPHA = 1. Only the condition where CPOL = 0 is
described.
Figure 20-37. DSPI Modified Transfer Format (MTFE = 1, CPHA = 1, f
SCK
= f
SYS
/ 4)
20.4.7.5 Continuous Selection Format
Some peripherals must be deselected between every transfer. Other peripherals must remain selected
between several sequential serial transfers. The continuous selection format provides the flexibility to
handle both cases. The continuous selection format is enabled for the SPI configuration by setting the
CONT bit in the SPI command. Continuous selection is enabled for the DSI configuration by setting the
DCONT bit in the DSPIx_DSICR. The behavior of the PCS signals in the two configurations is identical
so only the SPI configuration is described.
When the CONT bit = 0, the DSPI drives the asserted chip select signals to their idle states in between
frames. The idle states of the chip select signals are selected by the PCSIS field in the DSPIx_MCR.
t
CSC
= PCS to SCK delay.
t
ASC
= After SCK delay.
System clock
123456
PCS
t
ASC
SCK
Master sample
Master SOUT
Slave SOUT
Slave sample
t
CSC
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