Datasheet

324
6120F–ATARM–03-Oct-06
AT91SAM7X512/256/128 Preliminary
Figure 30-28. Normal Mode Configuration
30.6.8.2 Automatic Echo Mode
Automatic echo mode allows bit-by-bit retransmission. When a bit is received on the RXD pin, it
is sent to the TXD pin, as shown in Figure 30-29. Programming the transmitter has no effect on
the TXD pin. The RXD pin is still connected to the receiver input, thus the receiver remains
active.
Figure 30-29. Automatic Echo Mode Configuration
30.6.8.3 Local Loopback Mode
Local loopback mode connects the output of the transmitter directly to the input of the receiver,
as shown in Figure 30-30. The TXD and RXD pins are not used. The RXD pin has no effect on
the receiver and the TXD pin is continuously driven high, as in idle state.
Figure 30-30. Local Loopback Mode Configuration
30.6.8.4 Remote Loopback Mode
Remote loopback mode directly connects the RXD pin to the TXD pin, as shown in Figure 30-31.
The transmitter and the receiver are disabled and have no effect. This mode allows bit-by-bit
retransmission.
Receiver
Transmitter
RXD
TXD
Receiver
Transmitter
RXD
TXD
Receiver
Transmitter
RXD
TXD
1