LM3S2793 Datasheet, PDF (56/1194 Pages) Texas Instruments – Stellaris® LM3S2793 Microcontroller

Architectural Overview
1.3.4.4
1.3.4.5
■ Master with arbitration and clock synchronization, multimaster support, and 7-bit addressing
mode
SSI (see page 762)
Synchronous Serial Interface (SSI) is a four-wire bi-directional communications interface that converts
data between parallel and serial. The SSI module performs serial-to-parallel conversion on data
received from a peripheral device, and parallel-to-serial conversion on data transmitted to a peripheral
device. The SSI module can be configured as either a master or slave device. As a slave device,
the SSI module can also be configured to disable its output, which allows a master device to be
coupled with multiple slave devices. The TX and RX paths are buffered with separate internal FIFOs.
The SSI module also includes a programmable bit rate clock divider and prescaler to generate the
output serial clock derived from the SSI module's input clock. Bit rates are generated based on the
input clock and the maximum bit rate is determined by the connected peripheral.
The LM3S2793 microcontroller includes two SSI modules with the following features:
■ Programmable interface operation for Freescale SPI, MICROWIRE, 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 4 entries
– Transmit single request asserted when there is space in the FIFO; burst request asserted
when FIFO contains 4 entries
Inter-Integrated Circuit Sound (I²S) Interface (see page 842)
The I²S interface is a configurable serial audio core that contains a transmit module and a receive
module. The module is configurable for the I²S as well as Left-Justified and Right-Justified serial
audio formats. Data can be in one of four modes: Stereo, Mono, Compact 16-bit Stereo and Compact
8-Bit Stereo.
The transmit and receive modules each have an 8-entry audio-sample FIFO. An audio sample can
consist of a Left and Right Stereo sample, a Mono sample, or a Left and Right Compact Stereo
sample. In Compact 16-Bit Stereo, each FIFO entry contains both the 16-bit left and 16-bit right
samples, allowing efficient data transfers and requiring less memory space. In Compact 8-bit Stereo,
each FIFO entry contains an 8-bit left and an 8-bit right sample, reducing memory requirements
further.
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January 20, 2012
Texas Instruments-Production Data