Motorola 700/800-Series User Manual
Introduction
1-13
1
An asterisk (*) following the signal name for signals which are level
significant denotes that the signal is true or valid when the signal is
low.
significant denotes that the signal is true or valid when the signal is
low.
An asterisk (*) following the signal name for signals which are edge
significant denotes that the actions initiated by that signal occur on
high-to-low transition.
significant denotes that the actions initiated by that signal occur on
high-to-low transition.
In this manual, assertion and negation are used to specify forcing a
signal to a particular state. In particular, assertion and assert refer
to a signal that is active or true; negation and negate indicate a
signal that is inactive or false. These terms are used independently
of the voltage level (high or low) that they represent.
signal to a particular state. In particular, assertion and assert refer
to a signal that is active or true; negation and negate indicate a
signal that is inactive or false. These terms are used independently
of the voltage level (high or low) that they represent.
Data and address sizes are defined as follows:
❏
A byte is eight bits, numbered 0 through 7, with bit 0 being the
least significant.
least significant.
❏
A two-byte is 16 bits, numbered 0 through 15, with bit 0 being
the least significant. For the MVME162LX and other CISC
modules, this is called a word.
the least significant. For the MVME162LX and other CISC
modules, this is called a word.
❏
A four-byte is 32 bits, numbered 0 through 31, with bit 0 being
the least significant. For the MVME162LX and other CISC
modules, this is called a longword.
the least significant. For the MVME162LX and other CISC
modules, this is called a longword.
The terms control bit, status bit, true and false are used extensively in
this document.
this document.
The term control bit describes a bit in a register that can be set and
cleared under software control. The term true indicates that a bit is
in the state that enables the function it controls. The term false
indicates that the bit is in the state which disables the function it
controls. In all tables, the terms 0 and 1 describe the actual value
that should be written to the bit, or the value that it yields when
read.
cleared under software control. The term true indicates that a bit is
in the state that enables the function it controls. The term false
indicates that the bit is in the state which disables the function it
controls. In all tables, the terms 0 and 1 describe the actual value
that should be written to the bit, or the value that it yields when
read.
The term status bit describes a bit in a register that reflects a specific
condition. The status bit is read by software to determine
operational or exception conditions.
condition. The status bit is read by software to determine
operational or exception conditions.