Introduction
1447
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
M3 Synchronous Serial Interface (SSI)
20.1 Introduction
Each SSI is a master or slave interface for synchronous serial communication with peripheral devices that
have either Freescale SPI, or Texas Instruments Synchronous Serial Interfaces.
20.2 Features
The SSI module includes the following features:
•
Programmable interface operation for Freescale SPI, or Texas Instruments Synchronous Serial
Interfaces.
•
Master or slave operation
•
Programmable clock bit rate and prescaler
•
Separate transmit and receive FIFOs, each 16 bits wide and 8 locations deep
•
Programmable data frame size from 4 to 16 bits
•
Internal loopback test mode for diagnostic/debug testing
•
Standard FIFO-based interrupts and End-of-Transmission interrupt
•
Efficient transfers using Micro Direct Memory Access Controller (µDMA)
–
Separate channels for transmit and receive
–
Receive single request asserted when data is in the FIFO; burst request asserted when FIFO
contains four entries
–
Transmit single request asserted when there is space in the FIFO; burst request asserted when
FIFO contains four or more entries are available to be written in the FIFO
–
Maskable
μ
DMA interrupts for receive and transmit complete
20.2.1 SSI Block Diagram
The SSI module block diagram is shown in the figure below.