ICP DAS USA I-7188XA, User Manual

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I-7188XA Series User’s Manual ( Ver1.2, Feb/2014, 7MH-019-10 ) ---
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4.5 COM Port Comparison
The I-7188XA(D) COM ports are as follows:
COM Port Hardware
COM1 16C550, 9-wire RS-232 (Default) or 2-wire RS-485
COM2 16C550, 2-wire RS-485
COM3 80188’s on-chip UART-0, 3-wire RS-232
COM4 80188’s on-chip UART-1, 3-wire RS-232
The I-7188XA(D) COM Ports can be set as RS-232 or RS-485 as
below:
COM Port Type Pin name
2-wire RS-485 Data+, Data-
3-wire RS-232 TXD, RXD, GND
9-wire RS-232 TXD, RXD, GND, RTS, CTS, DCD, DTR, DSR, RI
The programming required for the 16C550 is very different from the
80188 UART. Interrupt handling on the 80188 is also very different from
the 8259 on a PC. Therefore, the RS-232 application programs for PC
are not executed in I-7188XA(D).
The software driver for the I-7188XA(D) is an interrupt driven library that
provides a 1K QUEUE buffer for each COM Port. The software is well
designed and easy to use.
The software driver provides the same interface for all four COM Ports,
so each port can be used in the same way without any difficulty.