Chapter 20 Deserial Serial Peripheral Interface (DSPI)
MPC5602P Microcontroller Reference Manual, Rev. 4
Freescale Semiconductor
439
— Continuously held chip select capability
•
8 peripheral chip selects, expandable to 64 with external demultiplexer
•
Deglitching support for as many as 32 peripheral chip selects with external demultiplexer
•
2 DMA conditions for SPI queues residing in RAM or flash
— TX FIFO is not full (TFFF)
— RX FIFO is not empty (RFDF)
•
6 interrupt conditions:
— End of queue reached (EOQF)
— TX FIFO is not full (TFFF)
— Transfer of current frame complete (TCF)
— RX FIFO is not empty (RFDF)
— FIFO overrun (attempt to transmit with an empty TX FIFO or serial frame received while RX
FIFO is full) (RFOF)
— FIFO under flow (slave only and SPI mode, the slave is asked to transfer data when the TX
FIFO is empty) (TFUF)
•
Modified SPI transfer formats for communication with slower peripheral devices
•
Continuous serial communications clock (SCK)
•
Maximum baud rate:
— Classic SPI Transfer Format—8 Mbit/s
— Modified SPI Transfer Format—16 Mbit/s
20.5
Modes of operation
The DSPI has four modes of operation. These modes can be divided into two categories; module-specific
modes such as master, slave, and module disable modes, and a second category that is an MCU-specific
mode: debug mode. All four modes are implemented on this device.
The module-specific modes are entered by host software writing to a register. The MCU-specific mode is
controlled by signals external to the DSPI. The MCU-specific mode is a mode that the entire device may
enter, in parallel to the DSPI being in one of its module-specific modes.
20.5.1
Master mode
Master mode allows the DSPI to initiate and control serial communication. In this mode, the SCK, CS
n
and SOUT signals are controlled by the DSPI and configured as outputs.
For more information, refer to
Section 20.8.1.1, “Master mode
.
20.5.2
Slave mode
Slave mode allows the DSPI to communicate with SPI bus masters. In this mode the DSPI responds to
externally controlled serial transfers. The DSPI cannot initiate serial transfers in slave mode. In slave
mode, the SCK signal and the CS0_
x
signal are configured as inputs and provided by a bus master. CS0_
x