Parallel Interface; Parallel Port Addressing And Interrupts - NEC POWERMATE 4100M Service Manual

Parallel Interface

The system has a 25-pin parallel port on the system board. Specifications for this port con-
form 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 inter-
rupt is selected to either IRQ5 or IRQ7 via the Setup and jumper settings.
Interrupt levels for the parallel port are given in Table Section 1-7. Software selectable base
addresses are 3BCh, 378h, and 278h.
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 shown in Appendix A.
Table Section 1-7 Parallel Port Addressing and Interrupts
Starting I/O Address
378
278
3BC
378*
278
3BC
*Default for parallel port
NOTE: Any interrupts used for the built-in par-
allel port is 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
1-15