Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK Data Sheet
Product codes
AT91SAM9N12-EK
920
SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]
11063K–ATARM–05-Nov-13
43.7.3 Receiver Operations
A received frame is triggered by a start event and can be followed by synchronization data before data transmission.
The frame synchronization is configured setting the Receive Frame Mode Register (
SSC_RFMR
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.
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.
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 43-9. Receiver Block Diagram
43.7.4 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.
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.
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 Register (RCMR/TCMR).
Thus, the start could be on TF (Transmit) or RF (Receive).
Thus, the start could be on TF (Transmit) or RF (Receive).
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).
(TFMR/RFMR).
SSC_RFMR.MSBF
SSC_RFMR.DATNB
SSC_TCMR.START
SSC_RCMR.START
SSC_RHR
SSC_RSHR
SSC_RFMR.FSLEN
SSC_RFMR.DATLEN
RX Controller counter reached STTDLY
RX Controller
RD
SSC_CR.RXEN
SSC_CR.RXDIS
SSC_SR.RXEN
Receiver Clock
RF
TXEN
RX Start
RF
RXEN
RC0R
SSC_RCMR.STTDLY != 0
Receive Shift Register
Start
Selector
Start
Selector
RX Start
load
load