Datasheet

13 Synchronous Serial Interface (SSI)
The Stellaris
®
Synchronous Serial Interface (SSI) is a master or slave interface for synchronous
serial communication with peripheral devices that have either Freescale SPI, MICROWIRE, or Texas
Instruments synchronous serial interfaces.
The Stellaris SSI module has the following features:
■ Master or slave operation
■ Programmable clock bit rate and prescale
■ Separate transmit and receive FIFOs, 16 bits wide, 8 locations deep
■ Programmable interface operation for Freescale SPI, MICROWIRE, or Texas Instruments
synchronous serial interfaces
■ Programmable data frame size from 4 to 16 bits
■ Internal loopback test mode for diagnostic/debug testing
13.1 Block Diagram
Figure 13-1. SSI Module Block Diagram
Transmit /
Receive
Logic
Clock
Prescaler
SSICPSR
SSICR0
SSICR1
SSISR
Interrupt Control
SSIIM
SSIMIS
SSIRIS
SSIICR
SSIDR
TxFIFO
8 x16
.
.
.
RxFIFO
8 x16
.
.
.
System Clock
SSITx
SSIRx
SSIClk
SSIFss
Interrupt
Identification
Registers
SSIPCellID0 0 SSIPeriphID 4
SSIPCellID1 1 SSIPeriphID 5
SSIPCellID2 2 SSIPeriphID 6
SSIPCellID3 SSIPeriphID 3 SSIPeriphID7
Control/ Status
SSIPeriphID
SSIPeriphID
SSIPeriphID
13.2 Signal Description
Table 13-1 on page 477 and Table 13-2 on page 477 list the external signals of the SSI module and
describe the function of each. The SSI signals are alternate functions for some GPIO signals and
June 18, 2012476
Texas Instruments-Production Data
Synchronous Serial Interface (SSI)
NRND: Not recommended for new designs.