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.

Table 1. Data Frame Registers
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

Figure 1. Transmit and Receive Frame Format in Edge/Pulse Start Modes

In the example illustrated in Transmit Frame Format in Continuous Mode (STTDLY = 0), the SSC_THR is loaded twice. The FSDEN value has no effect on the transmission. SyncData cannot be output in Continuous mode.

Figure 2. Transmit Frame Format in Continuous Mode (STTDLY = 0)

Figure 3. Receive Frame Format in Continuous Mode (STTDLY = 0)