3.7 RS232 Serial Ports(COM1, J23)
Both Universal Asynchronous Receivers/Transmitters (UARTs) are level shifted to
RS-232 levels.
The COM1 is the debug USART port of the AT91SAM9G20, that reaches the
external world through a male DB9 connector.
The others serial (UART0, UART2, UART3, UART4, UART5) reaches the external
world through a 2x10 pin berg header(J23). Please see follow table for the pin outs
of Serial connectors. The COM2, COM3 are 5-wire serial, and the others is 3-wire
serial serial.
Table J23 (USART0 - USART5) Connector
Pin
Signal Name
Function
1
GND
GND
2
GND
GND
3
RTXD0
UART0 TX
4
RTXD2
UART2 TX
5
RRXD0
UART0 RX
6
RRXD2
UART2 RX
7
RRTS0
UART0 RTS
8
RRTS2
UART2 RTS
9
RCTS0
UART0 CTS
10
RCTS2
UART2 CTS
11
RTXD4
UART4 TX
12
RTXD3
UART3 TX
13
RRXD4
UART4 RX
14
RRXD3
UART3 RX
15
RTXD5
UART5 TX
16
NC
17
RRXD5
UART5 RX
SBC-SAM9G20 User manual
www.armdevs.com
