at91sam9g20-cu ATMEL Corporation, at91sam9g20-cu Datasheet - Page 491

• Manufacturer Part Number: at91sam9g20-cu
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

32.6.8.1
32.6.8.2
32.6.8.3
32.6.8.4
6384B–ATARM–15-Dec-08
Normal Mode
Automatic Echo Mode
Local Loopback Mode
Remote Loopback Mode
Normal mode connects the RXD pin on the receiver input and the transmitter output on the TXD
pin.
Figure 32-38. Normal Mode Configuration
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
the TXD pin. The RXD pin is still connected to the receiver input, thus the receiver remains
active.
Figure 32-39. Automatic Echo Mode Configuration
Local loopback mode connects the output of the transmitter directly to the input of the receiver,
as shown in
the receiver and the TXD pin is continuously driven high, as in idle state.
Figure 32-40. Local Loopback Mode Configuration
Remote loopback mode directly 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
32-40. The TXD and RXD pins are not used. The RXD pin has no effect on
Transmitter
Transmitter
Transmitter
Receiver
Receiver
Receiver
Figure
32-39. Programming the transmitter has no effect on
AT91SAM9G20 Preliminary
1
RXD
TXD
RXD
TXD
RXD
TXD
Figure
32-41.
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