Atmel SAM4L-EK Atmel ATSAM4L-EK ATSAM4L-EK Data Sheet
Product codes
ATSAM4L-EK
616
42023E–SAM–07/2013
ATSAM4L8/L4/L2
Figure 24-53. ASK Modulator Output
Figure 24-54. FSK Modulator Output
24.6.17
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.
in three different test modes, with reconfigured pin functionality, as shown below.
24.6.17.1
Normal Mode
During normal operation, a receiver RXD pin is connected to a transmitter TXD pin.
Figure 24-55. Normal Mode Configuration
24.6.17.2
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
is also sent to the TXD pin, as shown in
. Transmitter configuration has no effect.
Manchester
encoded
data
default polarity
unipolar output
Txd
ASK Modulator
Output
Uptstream Frequency F0
NRZ stream
1
0
0
1
Manchester
encoded
data
default polarity
unipolar output
Txd
FSK Modulator
Output
Uptstream Frequencies
[F0, F0+offset]
NRZ stream
1
0
0
1
Receiver
Transmitter
RXD
TXD