16-Bit Microprocessor Handbook

TIMING DIAGRAM CONVENTIONS
Timing diagrams play an important part in the description of any microprocessor or support device. Timing
diagrams are therefore used extensively in this book. All timing diagrams observe the following conventions:
1) A low signal level is equivalent to no voltage. A high signal level is equivalent to voltage present:
No voltage
I
Voltage present
2) A single signal making a low-to-high transition like this:
low
I
high
3) A single signal making a high-to-Iow transition is illustrated like this:
high
\ low
4) When using two or more parallel signals exist. the notation:
r= signals change
I
states that one or more of the parallel signals change level. but the transition (high-to low or low-to-high) is
unspecified).
5) A three-state single signal is shown floating thus:
~-------~
Signal
floating
6) A three-state bus containing two or more signals is shown floating thus:
_______ r---~~---4~------
floating
7) When one signal condition triggers other signal changes. an arrow indicates the relationship as follows:
Cond'bon ~
h". J
Causes
change
here
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