45.8.7 Data Format
The data framing format of both the transmitter and the receiver are programmable through the Transmitter Frame Mode Register (SSC_TFMR) and the Receive Frame Mode Register (SSC_RFMR). In either case, the user can independently select the following parameters:
- Event that starts the data transfer (START)
- Delay in number of bit periods between the start event and the first data bit (STTDLY)
- Length of the data (DATLEN)
- Number of data to be transferred for each start event (DATNB)
- Length of synchronization transferred for each start event (FSLEN)
- Bit sense: most or least significant bit first (MSBF)
Additionally, the transmitter can be used to transfer synchronization and select the level driven on the TD pin while not in data transfer operation. This is done respectively by the Frame Sync Data Enable (FSDEN) and by the Data Default Value (DATDEF) bits in SSC_TFMR.
| Transmitter | Receiver | Field | Length | Comment |
|---|---|---|---|---|
| SSC_TFMR | SSC_RFMR | DATLEN | Up to 32 | Size of word |
| SSC_TFMR | SSC_RFMR | DATNB | Up to 16 | Number of words transmitted in frame |
| SSC_TFMR | SSC_RFMR | MSBF | – | Most significant bit first |
| SSC_TFMR | SSC_RFMR | FSLEN | Up to 256 | Size of Synchro data register |
| SSC_TFMR | – | DATDEF | 0 or 1 | Data default value ended |
| SSC_TFMR | – | FSDEN | – | Enable send SSC_TSHR |
| SSC_TCMR | SSC_RCMR | PERIOD | Up to 512 | Frame size |
| SSC_TCMR | SSC_RCMR | STTDLY | Up to 255 | Size of transmit start delay |
In the example illustrated above, the SSC_THR is loaded twice. The FSDEN value has no effect on the transmission. SyncData cannot be output in Continuous mode.
