# Digital Signal Source

In this topic:

## Netlist entry

Axxxx [ out_0 out_1 .. out_n ] model_name

## Connection details

 Name Description Flow Type out Output out d, vector

## Model format

.MODEL model_name d_source parameters

## Model parameters

 Name Description Type Default Limits input_file Digital input vector filename string none none out_family Output logic family string UNIV none out_res Digital output resistance real 100 $0 - \infty$ out_res_pos Digital output res. pos. slope real out_res $0 - \infty$ out_res_neg Digital output res. neg. slope out_res $0 - \infty$ min_sink Minimum sink current real -0.001 none max_source Maximum source current real 0.001 none

## Device Operation

The digital signal source provides a multi bit arbitrary digital signal defined in a file.

## File Format

The file is in ASCII format and is in the form of a table each row being on a new line. The first column defines the time values while the entries in the remaining columns define the output value for each of the outputs. So the total number of columns must be the number of outputs plus one. The output values must appear in the same order as the outputs in the netlist entry. So, the values for out_0 will be in column 2, out_1 in column 3 etc.

The file may include blank lines and comment lines beginning with a '*'.

The output values must specify the state as well as the strength using the following codes:

 Code State-Strength 0S LOW-STRONG 1S HIGH-STRONG US UNKNOWN-STRONG 0R LOW-RESISTIVE 1R HIGH-RESISTIVE UR UNKNOWN-RESISTIVE 0Z LOW-HI-Z 1Z HIGH-HI-Z UZ UNKNOWN-HI-Z 0U LOW-UNDETERMINED 1U HIGH-UNDETERMINED UU UNKNOWN-UNDETERMINED
Note, these codes are not case sensitive.

## Example

The following file:

* This is an example source file
0.0 0s 0s 0r 1s
1u 0s 0s 0r 0z
2u 0s 0s 1r 0z
5u 1s 0s 1r 0z
22e-6 1s 1s 1r 0z
50u 0s 1s 1r 0z
60u 0s 1s 1r 0z
70u 0s 1s 1r 0z
80u 0s 1s 1r 0z
90u Us Us Ur 0s

and this circuit:

Produces the following waveforms

An error will result if the file fails in any way to comply with the format. There must be the exact number of entries in each row and the time values must be monotonic. Totally blank lines or lines containing only white space are permitted but any other non-comment line not complying with the format will fail.