Deserial Serial Peripheral Interface (DSPI)
25-44
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
of how a DSPI can be used with a deserializing peripheral that supports SPI control for control and
diagnostic frames.
Figure 25-24. Example of System using DSPI in CSI Configuration
In CSI Configuration the DSPI transfers DSI data based on DSI Transfer Initiation Control. When there
are SPI commands in the TX FIFO, the SPI data has priority over the DSI frames. When the TX FIFO is
empty, DSI transfer resumes.
Two peripheral chip select signals indicate whether DSI data or SPI data is transmitted. The user must
configure the DSPI so that the two CTAR registers associated with DSI data and SPI data assert different
peripheral chip select signals denoted in the figure as PCSx and PCSy. The CSI Configuration is only
supported in Master Mode.
Data returned from the external slave while a DSI frame is transferred is placed on the Parallel Output
signals. Data returned from the external slave while a SPI frame is transferred is moved to the RX FIFO.
The TX FIFO and RX FIFO are fully functional in CSI mode.
25.4.5.1
CSI Serialization
Serialization in the CSI configuration is similar to serialization in DSI Configuration. The transfer
attributes for SPI frames are determined by the DSPI_CTAR register selected by the CTAS field in the SPI
command halfword. The transfer attributes for the DSI frames are determined by the DSPI_CTAR register
selected by the DSICTAS field in the DSPI_DSICR.
shows the CSI Serialization logic.
Shift Register
SIN
SIN
SOUT
SOUT
SCK
SCK
SSx
PCSx
DSPI Master
External Slave Deserializer
SSy
PCSy
SPI
Frame
Select
Logic
Frame
DSI
Frame
Shift Register
SPI
DSI
TX Priority
Control
TX FIFO
Summary of Contents for PXR4030
Page 1: ...PXR40 Microcontroller Reference Manual Devices Supported PXR4030 PXR4040 PXR40RM Rev 1 06 2011...
Page 30: ...PXR40 Microcontroller Reference Manual Rev 1 Freescale Semiconductor xxx...
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Page 66: ...Memory Map PXR40 Microcontroller Reference Manual Rev 1 2 4 Freescale Semiconductor...
Page 120: ...Signal Descriptions 3 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
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