Datasheet

6120F–ATARM–03-Oct-06

AT91SAM7X512/256/128 Preliminary

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.

Figure 31-9. Receiver Block Diagram

31.6.4 Start

The transmitter and receiver can both be programmed to start their operations when an event

occurs, respectively in the Transmit Start Selection (START) field of SSC_TCMR and in the

Receive Start Selection (START) field of SSC_RCMR.

Under the following conditions the start event is independently programmable:

• Continuous. In this case, the transmission starts as soon as a word is written in SSC_THR

and the reception starts as soon as the Receiver is enabled.

• Synchronously with the transmitter/receiver

• On detection of a falling/rising edge on TF/RF

• On detection of a low level/high level on TF/RF

• On detection of a level change or an edge on TF/RF

A start can be programmed in the same manner on either side of the Transmit/Receive Clock

Moreover, the Receiver can start when data is detected in the bit stream with the Compare

Functions.

Detection on TF/RF input/output is done by the field FSOS of the Transmit/Receive Frame

Mode Register (TFMR/RFMR).

Receive Shift Register

Start

Selector

SSC_RHRSSC_RSHR

Receiver Clock

SSC_RFMR.FSLEN SSC_RFMR.DATLEN

SSC_CR.RXEN

SSC_CR.RXDIS

SSC_SR.RXEN

SSC_RFMR.MSBF

SSC_RCMR.STTDLY

SSC_RFMR.DATNB