Table of Contents
Advertisement
3.3.11 COM Port Header
Dual RS-232/RS-422/RS-485 pin header- CN19
Pin
Signal RS-232 mode
1
COM1_RxD
COM1_Rx+
2
COM2_RxD
COM2_Rx+
3
COM1_TxD
COM1_Tx-
4
COM2_TxD
COM2_Tx-
5
GND
GND
7
COM1_RTS#
COM1_Tx+
8
COM2_RTS#
COM2_Tx+
9
COM1_CTS#
COM1_Rx-
10
COM2_CTS#
COM2_Rx-
COM1_RX+/COM1_RX-: COM port #1 RS-422 receive differential pair
COM1_TX+/COM1_TX-: COM port #1 RS-422 Transmit differential pair
COM2_RX+/COM2_RX-: COM port #2 Full Duplex RS-485 (RS-422) Receive differential pair
COM2_TX+/COM2_TX-: COM port #2 Full Duplex RS-485 (RS-422) Transmit differential pair
COM1_Data+/COM1_Data-: COM Port #1 Half Duplex RS-485 Differential Pair
COM2_Data+/COM2_Data-: COM Port #2 Half Duplex RS-485 Differential Pair
The selection of the kind of interface (RS-232, RS-422 or RS-485) can be made via BIOS (please check par. Errore. L'origine riferimento non è stata trovata.).
Please be aware that for proper RS-485 working, the RTS# signals must be used as a handshaking signal, i.e. it is used to control the data flow direction. When
RTS# signal is driven low, then the RS-485 port is in receiving mode, when RTS# signal is driven high then the RS-458 port is in transmitting mode.
SBC-C41-pITX
SBC-C41-pITX User Manual - Rev. First Edition: 1.0 - Last Edition: 1.1 - Author: A.R./S.B. - Reviewed by M.B. Copyright © 2021 SECO S.p.A.
Signal RS-422 mode
Signal RS-485 mode
COM1_Data-
COM2_Data-
GND
COM1_Data+
COM2_Data+
The embedded controller of SBC-C41 board manages two 4-
wire legacy UARTs, which are carried to as many
multistandard
RS-23/RS-422/RS-485
implementation of two multistandard serial ports (from now on respectively
named COM1 and COM2).
These ports are available on dedicated connector CN19, which is an internal
9-pin standard male pin header, p 2.54 mm, 5+4 pin, h = 6mm, type
NELTRON p/n 2213S-10G-E06 or equivalent.
Signals Description
COM1_RxD/COM2_RxD: COM port #1 / #2 RS-232 Receive data
COM1_TxD/COM2_TxD: COM port #1 / #2x RS-232 Transmit data
COM1_RTS#/COM2_RTS#: COM port #1 / #2 RS-232 Request to Send
handshaking signal.
COM1_CTS#/COM2_CTS#: COM port #1 / #2x RS-232 Clear To Send
handshaking signal
transceivers,
allowing
the
37
Advertisement
Table of Contents
