Parallel Interface; Serial Interface; Parallel Port Addressing And Interrupts - NEC POWERMATE V Service Manual

1-16 Technical Information

Parallel Interface

The system has a 25-pin parallel bidirectional enhanced parallel port on the system board.
Port specifications conform to the IBM-PC standards. The port supports Enhanced
Capabilities Port (ECP) and Enhanced Parallel Port (EPP) modes for devices that require
ECP or EPP protocols. The protocols allow high-speed bidirectional transfer over a parallel
port and increase parallel port functionality by supporting more devices.
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 selected to either IRQ5 or IRQ7 via Setup. Software selectable base addresses
are 3BCh, 378h, and 278h.
I/O addresses and interrupts for the parallel port are given in Table 1-8.
Table 1-8 Parallel Port Addressing and Interrupts
Starting I/O Address Interrupt Level
378
278
3BC
378
278
3BC
Parallel interface signals are output through the system board's 25-pin, D-subconnector.
The connector is located at the rear of the system unit. Pin locations for the parallel
interface connector are given in Appendix A.

Serial Interface

The system has two 16C550 UART compatible serial ports (COM1 and COM2) integrated
on the I/O controller. The serial ports support the standard RS-232C interface and the IrDA
interface (see Table 1-9). The buffered high-speed serial ports supports transfer rates up to
19.2 KB. These ports allow the installation of high-speed serial devices for faster data
transfer rates.
NOTE: Any interrupts used for the built-in
parallel port are not available for ISA parallel
ports.
IRQ05
IRQ05
IRQ05
IRQ07
IRQ07
IRQ07
Port
LPT1
LPT1 or LPT2
LPT1 or LPT2
LPT1
LPT1 or LPT2
LPT1 or LPT2