Atmel SAM4L Xplained Pro Starter Kit Atmel ATSAM4L-XSTK ATSAM4L-XSTK Data Sheet

42023E–SAM–07/2013

Figure 24-56. Automatic Echo Mode Configuration

Local loopback mode connects the output of the transmitter directly to the input of the receiver,
as shown in 

. 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 24-57. Local Loopback Mode Configuration

Remote loopback mode connects the RXD pin to the TXD pin, as shown in 

. The

transmitter and the receiver are disabled and have no effect. This mode allows bit-by-bit
retransmission.

Figure 24-58. Remote Loopback Mode Configuration

Receiver

Transmitter

RXD

TXD

Receiver

Transmitter

RXD

TXD

1

Receiver

Transmitter

RXD

TXD

1

MANEA

23

22

21

20

19

18

17

16

–

–

–

MANE

CTSIC

DCDIC– DSRIC–  RIIC– 

15

14

13

12

11

10

9

8

LINTC

LINID

NACK/LINBK

RXBUFF

–

ITER/UNRE

TXEMPTY

TIMEOUT