Specifications
CHAPTERS
PROGRAMMING INFORMATION
5.1
INTRODUCTION
This chapter provides information useful to programmers who intend to program Little
Board/PC
hardware directly. Normally the operating system, or the application software
program
itself, handles the hardware for you, so that you need not be concerned with direct
programming of the board's hardware. In addition,
the Little Board/PC's ROM-BIOS pro-
vides a high degree of compatibility with the IBM
PC
ROM-BIOS. Consequently, there
should be little need for custom programming.
Be sure to read Chapter 4 (Theory of Operation) before attempting to program the board's
hardware.
In
addition, the references listed in the beginning of Chapter 4 are highly recom-
mended, and
in
some cases contain information which will
be
essential to your direct pro-
gramming of the board's controllers.
5.2
SYSTEM
MEMORY
MAP
The V 40's memory address space
is
specified by
20
address bits. Therefore, it can address 1
megabyte of memory. The board's 1 megabyte of memory space
is
decoded as indicated in
Table
5-1.
5.3
I/O
ADDRESS
MAP
The
V4O's
I/O
address space
is
specified by sixteen address bits. However, as in the standard
PC architecture, the Little Board/PC only decodes the lower ten of these address bits. Cards
designed for use in a PC Expansion Bus must therefore reside within this
I/O
address space.
Table 5-2 provides a
detailed
listing
of
the
I/O
port
assignments
used
on
the
Little
Board/PC.
In
many cases, the ROM-BIOS functions provide all
of
the "hooks"
that
are
required for accessing devices connected the board's
I/O
ports.
If
direct programming of the
board's peripheral interfaces
is
necessary, refer to the individual technical data sheets for the
components used. These are available from the device manufacturers or through Ampro.
When adding cards
to
the
PC
Expansion Bus,
be
sure to check for
I/O
address conflicts.
Note that the
I/O
port addresses listed in Table 5-2 cannot be applied to the
PC
expansion
bus.
5-1