VISION
UDOO VISION User Manual - Rev. First Edition: 1.0 - Last Edition: 1.0 - Author: A.R. - Reviewed by M.B. Copyright © 2021 SECO S.p.A
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3.3.11
COM Port Header
The embedded controller of UDOO VISION board manages two 4-wire
legacy UARTs, which are carried to as many multistandard RS-232/RS-
422/RS-485 transceivers, allowing the 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
/COM1_RX-: COM port #1 RS-422 receive differential pair
/COM1_TX-: COM port #1 RS-422 Transmit differential pair
/COM2_RX-: COM port #2 Full Duplex RS-485 (RS-422) Receive differential pair
/COM2_TX-: COM port #2 Full Duplex RS-485 (RS-422) Transmit differential pair
CO/COM1_Data-: COM Port #1 Half Duplex RS-485 Differential Pair
CO/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 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.
Dual RS-232/RS-422/RS-485 pin header- CN19
Pin
Signal RS-232 mode
Signal RS-422 mode
Signal RS-485 mode
1
COM1_RxD
2
COM2_RxD
3
COM1_TxD
COM1_Tx-
COM1_Data-
4
COM2_TxD
COM2_Tx-
COM2_Data-
5
GND
GND
GND
7
COM1_RTS#
CO
8
COM2_RTS#
CO
9
COM1_CTS#
COM1_Rx-
10
COM2_CTS#
COM2_Rx-
