SAM7X256_14 Datasheet, PDF (342/662 Pages) ATMEL Corporation – ARM-based Flash MCU

To transmit data, the transmitter uses a shift register clocked by the transmitter clock signal and the start mode selected
in the SSC_TCMR. Data is written by the application to the SSC_THR register then transferred to the shift register
according to the data format selected.
When both the SSC_THR and the transmit shift register are empty, the status flag TXEMPTY is set in SSC_SR. When
the Transmit Holding register is transferred in the Transmit shift register, the status flag TXRDY is set in SSC_SR and
additional data can be loaded in the holding register.
Figure 31-8. Transmitter Block Diagram
SSC_CR.TXEN
SSC_SR.TXEN
SSC_CR.TXDIS
SSC_TFMR.DATDEF
1
SSC_TCMR.STTDLY
SSC_TFMR.FSDEN
SSC_TFMR.DATNB
SSC_TFMR.MSBF
0
TD
RF TF
Transmitter Clock _Start
Selector
Transmit Shift Register
SSC_TFMR.FSDEN
SSC_TCMR.STTDLY
0
1
SSC_TFMR.DATLEN
SSC_THR
SSC_TSHR
SSC_TFMR.FSLEN
31.6.3 Receiver Operations
A received frame is triggered by a start event and can be followed by synchronization data before data transmission.
The start event is configured setting the Receive Clock Mode Register (SSC_RCMR). See “Start” on page 343.
The frame synchronization is configured setting the Receive Frame Mode Register (SSC_RFMR). See “Frame Sync” on
page 345.
The receiver uses a shift register clocked by the receiver clock signal and the start mode selected in the SSC_RCMR.
The data is transferred from the shift register depending on the data format selected.
When the receiver shift register is full, the SSC transfers this data in the holding register, the status flag RXRDY is set in
SSC_SR and the data can be read in the receiver holding register. If another transfer occurs before read of the RHR
register, the status flag OVERUN is set in SSC_SR and the receiver shift register is transferred in the RHR register.
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
342