SAM7S256_14 Datasheet, PDF (387/775 Pages) ATMEL Corporation – ARM-based Flash MCU

31.6.8.2 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 31-31. Programming the transmitter has no effect on the TXD pin. The RXD pin is still con-
nected to the receiver input, thus the receiver remains active.
Figure 31-31. Automatic Echo Mode Configuration
Receiver
RXD
Transmitter
TXD
31.6.8.3 Local Loopback Mode
Local loopback mode connects the output of the transmitter directly to the input of the receiver, as shown in Figure
31-32. The TXD and RXD pins are not used. The RXD pin has no effect on the receiver and the TXD pin is contin-
uously driven high, as in idle state.
Figure 31-32. Local Loopback Mode Configuration
Receiver
RXD
Transmitter
TXD
1
31.6.8.4 Remote Loopback Mode
Remote loopback mode directly connects the RXD pin to the TXD pin, as shown in Figure 31-33. The transmitter
and the receiver are disabled and have no effect. This mode allows bit-by-bit retransmission.
Figure 31-33. Remote Loopback Mode Configuration
Receiver
1
RXD
Transmitter
TXD
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
387