MPC563XM Reference Manual, Rev. 1
1184
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
Figure 26-22. DSI Deserialization Diagram
26.5.4.5
DSI Transfer Initiation Control
Data transfers for a Master DSPI in DSI configuration are initiated by a condition. The transfer initiation
conditions are selected by the TRRE and CID bits in the DSPI_DSICR.
lists the four transfer
initiation conditions.
26.5.4.5.1
Continuous Control
For Continuous Control the initiation of a transfer is based on the baud rate at which data is transferred
between the DSPI and the external device. The baud rate is set in the DSPI_CTAR register selected by the
DSICTAS field in the DSPI_DSICR. A new DSI frame shifts out when the previous transfer cycle has
completed and the Delay after Transfer (t
DT
) has elapsed.
26.5.4.5.2
Change In Data Control
For Change in Data Control a transfer is initiated when the data to be serialized has changed since the
transfer of the last DSI frame. A copy of the previously transferred DSI data is stored in the
DSPI_COMPR. When the data in the DSPI_SDR or the DSPI_ASDR is different from the data in the
DSPI_COMPR a new DSI frame is transmitted. The TXSS bit in the DSPI_DSICR selects which register
the DSPI_COMPR is compared to. The MTRIG output signal is asserted every time a change in data is
detected.
Table 26-33. DSI Data Transfer Initiation Control
DSPI_DSICR Bits
Transfer Initiation Control
TRRE
CID
0
0
Continuous
0
1
Change in Data
1
0
Triggered
1
1
Triggered or Change in Data
SIN
Shift Register
0 1
N-1
Control
Logic
DSI Deserialization
Data Register
N
N
Parallel
Outputs
In TSB configuration the number of bits N = 32, for non TSB it values 16.
Slave Bus Interface