MPC563XM Reference Manual, Rev. 1
Freescale Semiconductor
1183
Preliminary—Subject to Change Without Notice
If the CID bit in the DSPI_DSICR is set and the data in the DSPI_COMPR differs from the selected source
of the serialized data, the slave DSPI will assert the MTRIG signal. If the slave’s HT signal is asserted and
the TRRE is set, the slave DSPI asserts MTRIG. These features are included to support chaining of several
DSPI. Details about the MTRIG signal is found in
Section 26.5.4.6, “Multiple Transfer Operation
26.5.4.3
DSI Serialization
In the DSI Configuration from four to sixteen bits can be serialized using two different sources. The TXSS
bit in the DSPI_DSICR selects between the DSPI DSI Serialization Data Register (DSPI_SDR) and the
DSPI DSI Alternate Serialization Data Register (DSPI_ASDR) as the source of the serialized data. The
DSPI_SDR holds the latest Parallel Input signal values which is sampled at every rising edge of the system
clock. The DSPI_ASDR register is written by host software and used as an alternate source of serialized
data.
A copy of the last 32-bit DSI frame shifted out of the Shift Register is stored in the DSPI DSI Transmit
Comparison Register (DSPI_COMPR). This register provides added visibility for debugging and it serves
as a reference for transfer initiation control.
shows the DSI Serialization logic.
Figure 26-21. DSI Serialization Diagram
26.5.4.4
DSI Deserialization
When all bits in a DSI frame have been shifted in, the frame is copied to the DSPI DSI Deserialization
Data Register (DSPI_DDR). This register presents the deserialized data as Parallel Output signal values.
The DSPI_DDR is memory mapped to allow host software to read the deserialized data directly.
shows the DSI Deserialization logic.
DSI Config.
SOUT
Shift Register
HT
0 1
15
Clock
Logic
SCK
TXSS
0
1
Register
Control
Logic
DSI Transmit
Comparison Register
PCS
DSI Serialization
Data Register
32
32
32
DSPI Alternate
Serialization Data Register
Parallel
Inputs
32
0
1
16
Slave Bus Interface