Ampro Corporation 5001451A manual Multi-Mode Parallel Port, Addresses and Interrupts

Little Board P6d Module

Table 2-18. IrDA Interface Pinout

J19 Pin #	Signal Name	Function
18	IRMODE /IRRXB	Fast IR Receive/Mode Input
19	IRTX	IR Transmit
20	IRRXA	IR Receive (SIR)

Multi-Mode Parallel Port

The Little Board P6d system incorporates a multi-mode parallel port. This port supports four modes of operation:

!Standard PC/AT printer port (output only)

!PS/2-compatible bidirectional parallel port (SPP)

!Enhanced Parallel Port (EPP)

!Extended Capabilities Port (ECP)

This section lists the pinout of the parallel port connector and describes how to configure it for its I/O port and interrupt assignments, how to assign a DMA channel to the port when operating in ECP mode. And programming information, including how to use the port for bidirectional I/O.

I/O Addresses and Interrupts

The parallel port functions are controlled by eight I/O ports and their associated register and control functionality. The Little Board P6d parallel port is assigned to the primary parallel port address normally assigned to LPT1 and cannot be changed. You may disable the port in Setup to free the hardware resources for other peripherals.

The parallel port can be configured to generate an interrupt request upon a variety of conditions, depending on the mode the port is in. Assignment of an interrupt to the parallel port is optional, and its use depends on software requirements and which mode of operation you are using. IRQ 7 is the default parallel port IRQ assignment. Table 2-19lists the parallel port addresses and IRQs.

Table 2-19. Parallel Printer I/O Addresses and Interrupt

Selection	I/O Address	Interrupt
Primary	378h - 37Fh	7
Secondary	278h - 27Fh	5
Secondary	3BCh - 3BFh	7
Disable	None	None

ROM-BIOS Installation of Parallel Ports

Normally, the BIOS assigns the name LPT1 to the primary parallel port, and LPT2 to the secondary parallel port (if present), and so on. However, the BIOS scans the standard addresses for parallel ports and if it only finds a secondary port, it assigns LPT1 to that one. Therefore, if the Little Board’s parallel port is enabled, it will be assigned LPT1 by the BIOS. If it is disabled and there is another parallel port in your system, that port will be assigned LPT1 by the BIOS.

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