Advantech UNO-3082, Руководство пользователя

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11 Chapter 2
2.2 RS-232/422/485 Interface (COM1~COM2)
The UNO-3084 offers two industrial RS-232/422/485 serial communica-
tion interface ports: COM1 and COM2. Please refer to Appendix A.5 for
their pin assignments. The default setting of COM1 and COM2 are RS-
422/485. (Please refer to section 2.2.4 for how to determine RS-232 or
RS-422/485)
2.2.1 16C950 UARTs with 16-byte FIFO Standard
Advantech UNO-3084 comes standard with Oxford 16PCI952 UART
(two OX16C950 UARTs, fully software compatible with 16C550) which
containing 128 bytes FIFOs. These upgraded FIFOs greatly reduce CPU
overhead and are an ideal choice for heavy multitasking environments.
2.2.2 RS-422/485 Jumperless Detection
In RS-422/485 mode, UNO-3084 automatically detects signals to match
RS-422 or RS-485 networks. (Refer to section 2.2.5)
2.2.3 Automatic Data Flow Control Function for RS-485
In RS-485 mode, UNO-3084 automatically detects the direction of incom-
ing data and switches its transmission direction accordingly. So no hand-
shaking signal (e.g. RTS signal) is necessary. This lets you easily build an
RS-485 network with Data+, Data- and Ground. More importantly, appli-
cation software previously written for full-duplex RS-232 environments
can be maintained without modification.
2.2.4 RS-232/422/485 Selection
COM1 and COM2 support 9-wire RS-232, RS-422 and RS-485 interfaces.
The system detects RS-422 or RS-485 signals automatically in RS-422/
485 modes. To select between RS-422/485 and RS-232 for COM1, adjust
CN28. To select between RS-422/485 and RS-232 for COM2, adjust
CN29.
You can refer to figures below to set the CN28 and CN29.
Note: Please refer to Appendix A.2 Figure A.3 for location
of CN28 and CN29 location.