Provided by: drawtiming_0.7.1-5_amd64 
NAME
drawtiming — generate timing diagram from signal description
SYNOPSIS
drawtiming [--verbose] [--scale factor] [--pagesize WxH] [--aspect] [--cell-height H]
[--cell-width W] [--font-size pts] [--line-width W] --output target file ...
DESCRIPTION
This application provides a command line tool for documenting hardware and software designs
through ideal timing diagrams. It reads signal descriptions from a text file with an
intuitive syntax, and outputs an ideal timing diagram to an image file. Notation typical of
timing diagrams found in the Electrical Engineering discipline is used, including arrows
indicating causal relationships between signal transitions.
The options are as follows:
--help Show usage reminder.
--verbose Increase diagnostic output.
--scale factor
Scale the diagram by the given factor. The default scaling factor is 1.0.
--pagesize WidthxHeight
Scale the diagram to fit given image size.
--aspect Maintain fixed aspect ratio if --pagesize given.
--cell-height H
Height of the each signal in pixels. Default is 32.
--cell-width W
Width for the time unit in pixels. Defaults is 64.
--font-size pts
Font size in pts. Default is 18.
--line-width W
Line width for drawings in pixels. Default is 1.
--output target
The name and format of the output image is determined by target.
file ... The input files describe the signals to be diagrammed. See the FILES and
EXAMPLES sections for a description of their format.
FILES
The following is a technical description of the input file syntax and semantics. If you are
reading this for the first time, you may want to skip ahead to the EXAMPLES section.
The input file consists of a series of statements describing the signal transitions during
each clock period of the timing diagram. Whitespace and comments following a ‘#’ are
ignored.
SIGNAL=VALUE This statement changes the value of a signal at the beginning of the current
clock, and adds it to the list of signal dependencies. The signal name may
consist of one or more words consisting of alphanumerics and underscores
joined by periods, ‘signal.name’, for example. The signal value format is
described further on.
SIGNAL This statement adds a signal to the list of dependencies without changing its
value.
Statements are separated by the following symbols:
, The comma separator is used to separate statements without affecting the dependency
list or clock (ie: the next statement will add to the dependency list).
; The semicolon separator resets the list of dependencies without incrementing the clock
. The period separator resets the list of dependencies and increments the clock.
=> The "causes" separator renders dependency arrows based on the current list of
dependencies and then resets the dependency list.
-tD> The "delay" separator renders a delay arrow from the last dependency with the
annotation tD.
Signal values are rendered according to the following rules:
0, 1, true, false A binary high/low signal.
tick A clock pulse which repeats.
pulse A one-shot clock pulse.
X A don't care value.
Z A tristate value.
"ABC" Any other alphanumeric token, or text enclosed in quotes is rendered as a
state. For example, ‘"1"’, is rendered as a state, whereas, ‘1’, is
rendered as a high signal.
EXAMPLES
Let's look at an example input file, and parse its meaning.
POWER=0, FIRE=0, ARMED=0, LED=OFF, COUNT=N.
POWER=1 => LED=GREEN.
FIRE=1.
FIRE => ARMED=1.
FIRE=0.
FIRE=1.
FIRE, ARMED => LED=RED;
FIRE => COUNT="N+1".
This input file descibes the changes in five signals over a period of seven clock cycles.
The end of each clock cycle is indicated with a period. For example, the following line
indicates a single signal, named ‘FIRE’ became true during a clock cycle:
FIRE=1.
The first clock period of the input file provides the initial value for all signals to be
diagrammed. The signals will appear on the timing diagram in the order they first appear in
the input file. Signals are assumed to have the "don't care" value if their initial value
is not given.
Independent signal transitions which occur simultaneously are normally separated by commas.
Since signals aren't normally expected to change simultaneously, the initial state is a good
example of this:
POWER=0, FIRE=0, ARMED=0, LED=OFF, COUNT=N.
Dependencies can also be indicated for a signal transition. Dependencies are rendered as
arrows on the timing diagram from the last change in each dependency to the dependent signal
transition. Here, the previous change in the state of ‘FIRE’ causes a change in the ‘ARMED’
signal.
FIRE => ARMED=1.
To indicate that a change in one signal causes an immediate change in another signal, list
both signal changes in the same clock period:
POWER=1 => LED=GREEN.
For signal state changes with multiple dependencies, separate the dependencies with commas:
FIRE, ARMED => LED=RED.
Sometimes, a single dependency causes multiple independent signals to change. Use a
semicolon to start a new list of dependencies. Modifying the previous line to indicate that
‘FIRE’ also causes ‘COUNT’ to increment yields:
FIRE, ARMED => LED=RED;
FIRE => COUNT="N+1".
You can find this example and others along with their generated timing diagrams on the
homepage for drawtiming at ‘http://drawtiming.sourceforge.net’.
DIAGNOSTICS
Exit status is 0 on success, and 2 if the command fails.
COMPATIBILITY
The drawtiming command has been tested on FreeBSD, Linux, and Cygwin.
AUTHORS
This software package was written by Edward Counce <ecounce@users.sourceforge.net>
Additional modifications by
Salvador E. Tropea <set@users.sourceforge.net>
Daniel Beer
BUGS
None reported.