Parallel Interface; Serial Interface; Parallel Port Addressing And Interrupts - NEC PowerMate VP75 User Manual

Parallel Interface

The system has a 25-pin parallel port on the system board. Specifications for this port conform to
the IBM-PC standards.
The BIOS has automatic ISA printer port sensing. If the BIOS detects an ISA printer port
mapped to the same address, the built-in printer port is disabled. The BIOS also sets the first
parallel interface port it finds as LPT1 and the second port it finds as LPT2. The interrupt is se-
lected to either IRQ5 or IRQ7 via the Setup and jumper settings.
Interrupt levels for the parallel port are given in Table Section 1-6. Software selectable base
addresses are 3BCh, 378h, and 278h.
Parallel interface signals are output through the system board's 25-pin, D-subconnector. The con-
nector is located at the rear of the system unit. Pin locations for the parallel interface connector
are shown in Appendix A.
Table Section 1-6 Parallel Port Addressing and Interrupts
Starting I/O Address
378
278
3BC
378*
278
3BC
*Default for parallel port

Serial Interface

The system has two standard serial ports (COM1 and COM2). The serial ports support the
standard RS-232C interface (16550 compatible). I/O addresses and interrupt levels for the two
channels are given in Table Section 1-7. The interrupt is selectable via Setup to either IRQ3 or
IRQ4. Software selectable base addresses are 3F8h, 2F8h, 3E8h, and 2E8h. Serial interface sig-
nals are output through the system board's 9-pin, D-subconnector. The connectors are located at
the rear of the system unit. Pin locations for the serial interface connector are shown in Appendix
A.
NOTE: Any interrupts used for the built-in
parallel port are not available for ISA parallel ports.
Interrupt Level
IRQ05
IRQ05
IRQ05
IRQ07
IRQ07
IRQ07
Technical Information
Port
LPT1
LPT1 or LPT2
LPT1 or LPT2
LPT1
LPT1 or LPT2
LPT1 or LPT2
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