Uart; Usart - Atmel SAM4E-EK User Manual

4.3.6

UART

The Universal Asynchronous Receiver Transmitter features a two-pin UART that can be used for communication and
trace purposes. It offers an ideal channel for in-situ programming solutions. This UART is associated with two PDC
channels to reduce the processor time on packet handling.
This two-pin UART (TXD and RXD only) is buffered through an RS232 Transceiver MN6 and brought to the DB9 male
connector J7.
Figure 4-5. UART.
+3V3 +3V3
R58 R59
100K 100K
UTXD0
PA10
PA9
URXD0 R60
R62
TP4
4.3.7

USART

The Universal Synchronous/Asynchronous Receiver Transmitter (USART) provides one full duplex universal
synchronous/asynchronous serial link. The data frame format is extensively configurable (data length, parity, number of
stop bits) to support a broad range of serial communication standards. The USART is also associated with PDC
channels for TX/RX data access.
To avoid any electrical conflict, the RS232 and RS485 transceiver are isolated from the receiving line PA21.
•
Chose RS485 channel: Close 1-2 pins on JP11 and set PA23 to high level
•
Chose RS232 channel: Close 2-3 pins on JP11 and set PA23 to low level
Figure 4-6. USART.
+3V3
+3V3
PA23 R37
PA22 R39
TXD1
PA21_232
RXD1 R40
PA24 R41
RTS1
PA25
CTS1 R42
R43
+3V3
DBGU
MN7
ADM3202
+3V3
16
VCC C1+
C54
100nF
2
V+ C1-
C55
6
100nF
V- C2+
C56
100nF
15
GND C2-
11
T1IN T1OUT
12
0R
R1OUT R1IN
10
T2IN T2OUT
9
0R
R2OUT R2IN
TP5
USART1
MN5
ADM3312EARU
3
VCC C1+
C43 C45 C44
4.7uF 100nF 100nF
1
V+ C1-
C2+
21
V-
C48
100nF
C2-
23
R38 GND C3+
47K
19
SD
5
0R
EN C3-
7
0R
T1IN T1OUT
10
0R
R1OUT R1IN
8
0R
T2IN T2OUT
11
0R
R2OUT R2IN
9
47K
T3IN T3OUT
12
R3OUT R3IN
1
C53
100nF
3
4
C57
100nF
5
14
13
7
8
6
C46
100nF
20
2
C47
100nF
4
24
J5
1
C49
6
100nF
22 2
7
18 3
15 8
17 4
14 9
16 5
R44 0R
13
PA21_485
FGND
JP11
PA21
2
PA21_232
J7
1
6
2
7
3
8
4
9
5
FGND
SAM4E-EK User Guide
42067B−SAM4E−04/2013
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