Техническая Спецификация для Atmel Evaluation Kit for AT32uC3A0512, 32-Bit AVR Microcontroller Atmel ATEVK1105 ATEVK1105
Модели
ATEVK1105
337
AT32UC3A
26.7.9
Test Modes
The USART can be programmed to operate in three different test modes. The internal loopback
capability allows on-board diagnostics. In the loopback mode the USART interface pins are dis-
connected or not and reconfigured for loopback internally or externally.
26.7.9.1
Normal Mode
Normal mode connects the RXD pin on the receiver input and the transmitter output on the TXD
pin.
Figure 26-40.
Normal Mode Configuration
26.7.9.2
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
. 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 26-41.
Automatic Echo Mode Configuration
26.7.9.3
Local Loopback Mode
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 26-42.
Local Loopback Mode Configuration
Receiver
Transmitter
RXD
TXD
Receiver
Transmitter
RXD
TXD
Receiver
Transmitter
RXD
TXD
1
32058K
AVR32-01/12