Notational Conventions; Values; Ranges; Signal Labels - Compaq Deskpro EXS Technical Reference Manual

Chapter 1 Introduction
1.3

NOTATIONAL CONVENTIONS

1.3.1 VALUES

Hexadecimal values are indicated by a numerical or alpha-numerical value followed by the letter
"h." Binary values are indicated by a value of ones and zeros followed by the letter "b."
Numerical values that have no succeeding letter can be assumed to be decimal.

1.3.2 RANGES

Ranges or limits for a parameter are shown using the following methods:
Example A:
Example B:

1.3.3 SIGNAL LABELS

Signal names are indicated using abbreviations, acronyms, or, if possible, the full signal name in
all capital letters. Signals that are meant to be active (asserted) low are indicated with a dash
immediately following the name.

1.3.4 REGISTER NOTATION AND USAGE

This guide uses standard Intel naming conventions in discussing the microprocessor's (CPU)
internal registers. Registers that are accessed through programmable I/O using an indexing scheme
are indicated using the following format:
In the example above, register 03C5.17h is accessed by writing the index port value 17h to the
index address (03C4h), followed by a write to or a read from port 03C5h.

1.3.5 BIT NOTATION

Bit values are labeled with bit <0> representing the least-significant bit (LSb) and bit <7>
representing the most-significant bit (MSb) of a byte. Bytes, words, double words, and quad words
are typically shown with most-significant portions on the left or top and the least-significant
portions on the right or bottom respectively.
1-2 Compaq Deskpro EXS and Workstation 300 Personal Computers
Featuring the Intel Pentium 4 Processor
Bits <7..4> = bits 7, 6, 5, and 4.
IRQ3-7, 9 = IRQ signals 3 through 7, and IRQ signal 9
03C5.17h
Index port
Data port
First Edition – December 2000