Synchronous Serial Interface (SSI)
17 Synchronous Serial Interface (SSI)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
17.1 Introduction
The Synchronous Serial Interface (SSI) module provides the functionality for synchronous serial
communications with peripheral devices, and can be configured to use either the Motorola® SPI™,
National Semiconductor® Microwire, or the Texas Instruments® synchronous serial interface
frame formats. The size of the data frame is also configurable, and can be set to be between 4
and 16 bits, inclusive.
The SSI module performs serial-to-parallel data conversion on data received from a peripheral
device, and parallel-to-serial conversion on data transmitted to a peripheral device. The TX and RX
paths are buffered with internal FIFOs allowing up to eight 16-bit values to be stored independently.
The SSI module can be configured as either a master or a 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 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 supported by the connected peripheral.
For devices that include a DMA controller, the SSI module also provides a DMA interface to facilitate
data transfer via DMA.
17.2 Functions
Functions
bool ROM_SSIBusy (uint32_t ui32Base)
uint32_t ROM_SSIClockSourceGet (uint32_t ui32Base)
void ROM_SSIClockSourceSet (uint32_t ui32Base, uint32_t ui32Source)
void ROM_SSIConfigSetExpClk (uint32_t ui32Base, uint32_t ui32SSIClk, uint32_t
ui32Protocol, uint32_t ui32Mode, uint32_t ui32BitRate, uint32_t ui32DataWidth)
void ROM_SSIDataGet (uint32_t ui32Base, uint32_t ∗pui32Data)
int32_t ROM_SSIDataGetNonBlocking (uint32_t ui32Base, uint32_t ∗pui32Data)
void ROM_SSIDataPut (uint32_t ui32Base, uint32_t ui32Data)
int32_t ROM_SSIDataPutNonBlocking (uint32_t ui32Base, uint32_t ui32Data)
void ROM_SSIDisable (uint32_t ui32Base)
void ROM_SSIDMADisable (uint32_t ui32Base, uint32_t ui32DMAFlags)
void ROM_SSIDMAEnable (uint32_t ui32Base, uint32_t ui32DMAFlags)
void ROM_SSIEnable (uint32_t ui32Base)
void ROM_SSIIntClear (uint32_t ui32Base, uint32_t ui32IntFlags)
void ROM_SSIIntDisable (uint32_t ui32Base, uint32_t ui32IntFlags)
April 8, 2013 185
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