Ampro Corporation 486E Bi-Directional Parallel Port, Register Name Address Primary Secondary

Product Reference

Bi-Directional Parallel Port

The Little Board/486e CPU incorporates a standard PC bi-directional parallel port at connector

J15. This port supports two modes of operation:

!Standard PC/AT printer port (output only)

!PS/2 compatible bi-directional parallel port (SPP)

Information about parallel port configuration using SETUP, is provided in this chapter. The low- level software interface to the parallel port consists of three addressable registers. The address map of these registers is shown in Table 2–15.

Table 2–15. Parallel Port Register Map

Register Name

Address

Primary Secondary

Data Port	378h	278h
Status Port	379h	279h
Control Port	37Ah	27Ah

I/O Addresses

Four I/O ports control the parallel port functions. Enabling the base I/O address permits configuration of the primary parallel port (typically LPT1), the secondary parallel port (typically LPT2), or you can disable the port to free its hardware resources for other peripherals you install on the PC/104 bus. Table 2–16 lists the resources used by the parallel port.

Table 2–16. Parallel Port Configuration

Selection	I/O Address	Interrupts
Primary	378h - 37Fh	IRQ 7
Secondary	278h - 27Fh	IRQ5
Disable	None	N/A

2–21