WaveJSON.md

The following set of structures used by WaveDrom rendering engine to describe timing diagrams. The format based on JSON syntax with some reserved keywords and structural limitations.

See WaveDrom Tutorial for examples.

signal

The the main root object. The value is the array of signal values.

{ "signal" : [
    value1,
    value2,
    ...
]}

signal value of array type represent a signal group. Where the first value in array is the group label of type string. Signal groups can be recursive.

{ "signal" : [
    [ "Group 1", value1 ],
    value2,
    ...
]}

signal object of object type represent the signal descriptor.

The empty signal object will causes empty gap between signals.

{ "signal" : [
    [ "Group 1", { signal object 1 }, { signal object 2 } ],
    ...
    {}, <-- gap between signal lanes
    ...
    { signal object 3 },
    ...
]}

signal...name

The string type. This value will be visible as signal label.

Example:

{ "signal" : [
    { "name" : "My Signal" }
]}

signal...wave

The string type. The signal lane activity. Each character represent single cycle.

{ "signal" : [
    { "wave" : "x.01.=.." }
]}

• p - when first in string creates positive edged clock wave
• n - when first in string creates negative edged clock wave
• P - same as p but with arrow
• N - same as n but with arrow
• 0 - low level
• 1 - high level
• = - value (default color 2)
• 2 - value with color 2
• 3 - value with color 3
• 4 - value with color 4
• 5 - value with color 5
• x - undefined value
• . - extends previous cycle
• z - high-impedance state
• u - pull-up (weak 1)
• d - pull-down (weak 0)
• | - extends previous cycle and draw gap on top of it

signal...data

Is an array of signal labels. Each value slot of signal lane can be labeled using this field.

{ "signal" : [
    { "data" : ["A", "B", "C"] }
]}

signal...period

signal period of number type. Expected natural number (1, 2, 3, 4 ...)

signal...phase

signal phase of number type. Positive number represent shift into the future. Negative number represents shift into past (delay).

signal...node

is the string. Each character represent a single cycle.

{ "signal" : [
    { "name" : "My Signal", "node" : "...a...b..C..." }
]}

• . - no marker
• [A-Z] - invisible marker
• other - visible marker

Other signal object strings will be ignored by WaveDrom rendering engine.

edge

The pair inside the root object. The edge's value holds the description of dependency arrows in form of array of strings

{ "signal" : [ v1, v2, ... ],
  "edge"   : array
}

Each element of edge array is a single string that describes an arrow or line (arrow string).

{ ...
  "edge"   : ["a->b edge 1", "b-~>c My Second Edge"]
}

Arrow string may contain multiple words separated by spaces. The first word defines the from and to points, the arrow shape and arrow label position. The rest of the text (after first space gap) will be placed as the label on top of arrow.

Special syntax can be used in the first word. First character is the from label. The last character is the to identifier. The character > in second from the end position will produce the arrow header. The rest of the symbols will affect the arrow shape.

• - - move arrow horizontally (x+)
• | - move arrow vertically (y+)
• ~ - makes the curvy shape (x+, y+)
• / - adds diagonal line (x+, y+)
• # - indicates the arrow label position

config

config.hscale

number >= 1 defines horizontal scale of timing diagram.

See WaveDrom Tutorial for more information.