MPC563XM Reference Manual, Rev. 1
Freescale Semiconductor
1185
Preliminary—Subject to Change Without Notice
26.5.4.5.3
Triggered Control
For Triggered Control initiation of a transfer is controlled by the Hardware Trigger signal (HT). The TPOL
bit in the DSPI_DSICR selects the active edge of HT. For HT to have any affect, the TRRE bit in the
DSPI_DSICR must be set.
26.5.4.5.4
Triggered or Change In Data Control
For Triggered or Change in Data Control initiation of a transfer is controlled by the HT signal or by the
detection of a change in data to be serialized.
26.5.4.6
Multiple Transfer Operation (MTO)
In DSI Configuration the MTO feature allows for multiple DSPIs within an SoC to be chained together in
a parallel or serial configuration. The parallel chaining allows multiple DSPIs internal to an SoC and
multiple SPI devices external to an SoC to share SCK and PCS signals thereby saving pins. The serial
chaining allows bits from multiple DSPIs to be concatenated into a single DSI frame. MTO is enabled by
setting the MTOE bit in the DSPI_DSICR.
In parallel and serial chaining there is one bus master and multiple bus slaves. The bus master initiates and
controls the transfers, but the DSPI slaves generate trigger signals for the bus DSPI master when an
internal condition in the slave warrants a transfer. The DSPI slaves also propagate triggers from other
slaves to the master. When a DSPI slave detects a trigger signal on its HT input, the slave generates a
trigger signal on the MTRIG output.
Serial and parallel chaining require multiplexing of signals external to the DSPI.
26.5.4.6.1
Parallel Chaining
Parallel chaining allows multiple DSPIs internal to an SoC and multiple SPI/DSI devices external to an
SoC to share common SCK and PCS signals thereby saving pins. Two pins are saved per pair of DSPI/SPI.
shows an example of how the blocks can be connected in an SoC.