<and>
Encloses replaceable terms for assembler syntax where they appear in code or code fragments.
For example:
MRC p15, 0, <Rd>, <CRn>, <CRm>, <Opcode_2>
SMALL CAPITALS
Used in body text for a few terms that have specific technical meanings, that are defined in the
Arm
®
Glossary
. For example,
IMPLEMENTATION DEFINED
,
IMPLEMENTATION SPECIFIC
,
UNKNOWN
, and
UNPREDICTABLE
.
Timing diagrams
The following figure explains the components used in timing diagrams. Variations, when they occur,
have clear labels. You must not assume any timing information that is not explicit in the diagrams.
Shaded bus and signal areas are undefined, so the bus or signal can assume any value within the shaded
area at that time. The actual level is unimportant and does not affect normal operation.
Clock
HIGH to LOW
Transient
HIGH/LOW to HIGH
Bus stable
Bus to high impedance
Bus change
High impedance to stable bus
Figure 1 Key to timing diagram conventions
Signals
The signal conventions are:
Signal level
The level of an asserted signal depends on whether the signal is active-HIGH or active-LOW.
Asserted means:
• HIGH for active-HIGH signals.
• LOW for active-LOW signals.
Lowercase n
At the start or end of a signal name, n denotes an active-LOW signal.
Additional reading
This book contains information that is specific to this product. See the following documents for other
relevant information.
Preface
About this book
101489_0000_02_en
Copyright © 2019, 2020 Arm Limited or its affiliates. All rights
reserved.
8
Non-Confidential - Beta