Datasheet

588
32072H–AVR32–10/2012
AT32UC3A3
Figure 25-52. ASK Modulator Output
Figure 25-53. FSK Modulator Output
25.6.17 Test Modes
The internal loopback feature enables on-board diagnostics, and allows the USART to operate
in three different test modes, with reconfigured pin functionality, as shown below.
25.6.17.1 Normal Mode
During normal operation, a receiver RXD pin is connected to a transmitter TXD pin.
Figure 25-54. Normal Mode Configuration
25.6.17.2 Automatic Echo Mode
Automatic echo mode allows bit-by-bit retransmission. When a bit is received on the RXD pin, it
is also sent to the TXD pin, as shown in Figure 25-55. Transmitter configuration has no effect.
Manchester
encoded
data
default polarity
unipolar output
Txd
ASK Modulator
Output
Uptstream Frequency F0
NRZ stream
10 0 1
Manchester
encoded
data
default polarity
unipolar output
Txd
FSK Modulator
Output
Uptstream Frequencies
[F0, F0+offset]
NRZ stream
10 0 1
Receiver
Transmitter
RXD
TXD