Motorola MVME2300 Series - Manual (Page 23)

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For example, “12” is the decimal number twelve, and “$12” is the decimal
number eighteen.
Unless otherwise specified, all address references are in hexadecimal.
In descriptions of the VMEbus interface, 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. 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.
In references to other bus signals (such as PCI) found on MVME2300
series boards, an underscore (_) or pound sign (#) following the signal
name denotes an active low signal.
In this manual, assertion and negation signify the forcing of 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.
Data and address sizes for MPC60x chips are defined as follows:
❏ A byte is eight bits, numbered 0 through 7, with bit 0 being the least
significant.
❏ A half-word is 16 bits, numbered 0 through 15, with bit 0 being the
least significant.
❏ A word or single word is 32 bits, numbered 0 through 31, with bit 0
being the least significant.
❏ A double word is 64 bits, numbered 0 through 63, with bit 0 being
the least significant.
Refer to Endian Issues in Chapter 5 for a discussion of which elements on
MVME2300 series boards use big-endian byte ordering, and which use
small-endian byte ordering.
The terms control bit and status bit are used extensively in this document.
The term control bit is used to describe a bit in a register that can be set and
cleared under software control. The term true is used to indicate that a bit
is in the state that enables the function it controls. The term false is used to