NXP Semiconductors MPC5606S - Continuous Selection Format

Deserial Serial Peripheral Interface (DSPI)
MPC5606S Microcontroller Reference Manual, Rev. 7
322 Freescale Semiconductor
Figure 11-17 shows the modified transfer format for CPHA = 1. Only the condition where CPOL = 0 is
described.
Figure 11-17. DSPI modified transfer format (MTFE = 1, CPHA = 1, f
SCK
= f
SYS
/ 4)
11.8.5.5 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.
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.
Figure 11-18 shows the timing diagram for two four-bit transfers with CPHA = 1 and CONT = 0.
Figure 11-18. Example of non-continuous format (CPHA = 1, CONT = 0)
t
CSC
= CS to SCK delay.
t
ASC
= After SCK delay.
System clock
123456
CS
t
ASC
SCK
Master sample
Master SOUT
Slave SOUT
Slave sample
t
CSC
SCK
(CPOL = 0)
CSx
t
ASC
SCK
(CPOL = 1)
Master SOUT
t
DT
t
CSC
t
CSC
= CS to SCK delay.
t
ASC
= After SCK delay.
t
DT
= Delay after transfer (minimum CS negation time).
Master SIN
t
CSC