46.8.2 Transmit Operations

A transmit frame is triggered by a start event and can be followed by synchronization data before data transmission.

The start event is configured by setting the SSC_TCMR. See Start.

The frame synchronization is configured setting the Transmit Frame Mode Register (SSC_TFMR). See Frame Synchronization.

To transmit data, the transmitter uses a shift register clocked by the transmit clock signal and the start mode selected in the SSC_TCMR. Data are input by the application into the transmit FIFO by writing to the Transmit Holding FIFO register (SSC_THFR). Once the transmit FIFO threshold programmed in the FIFO Mode register (SSC_FFMR.THRS) has been reached, data can be transferred to the transmit shift register according to the data format selected.

When both the transmit Holding FIFO and the transmit shift register are empty, the status flag TXEMPTY is set in the Status register (SSC_SR). As long as there is room left for writing new data into the transmit FIFO, the status flag TXRDY is set in the SSC_SR and additional data can be loaded in the Transmit Holding FIFO register. The number of remaining free data slots in the transmit FIFO is indicated by the SSC_SR.TXFRECNT field.