Programmable Logic Array
| Library: | Input/Output-Extra |
Behavior
Implements a programmable sum-of-products function. Each row in the editor is an AND term. A row can select the normal or complemented form of each input bit; the second plane connects selected AND terms to output OR gates. The configured matrix is stored with the circuit.
An AND term with no selected input literal produces an error value. An output with no connected AND term also produces an error value. When chip select is inactive, every output bit is unknown.
Pins
- Input
- A bus whose width is selected by
Input Bit Width
. - Output
- A bus whose width is selected by
Output Bit Width
. - sel (1 bit)
-
Chip select. Its active level is selected by
Select
; the default is active low.
Attributes
- Input Bit Width
- Selects from 1 through 32 input bits.
- Number of And Gates
- Selects from 1 through 32 product terms.
- Output Bit Width
- Selects from 1 through 32 output bits.
- Label
- The text associated with the component.
- Label Font
- The font used to draw the label.
- Label Visible
- Controls whether the label is displayed.
- Contents
- Opens the programmable matrix editor.
- Select
- Selects whether the chip-select input is active low or active high.
Editing the Matrix
Click Contents
in the attribute table, or use Edit Contents…
in the
component's context menu. In the input plane, click the intersection with an input or its
complement to add or remove that literal. In the output plane, click an intersection to
connect or disconnect an AND term from an output. Selecting one polarity of an input
automatically clears the other polarity in the same term. The context menu also provides
Clear Contents
.
Poke Tool Behavior
None. Use the Contents attribute or the component's context menu to edit the matrix.
Text Tool Behavior
Allows the label associated with the component to be edited.