Sources
In this topic:
Digital Pulse
Netlist entry
Axxxx out model_name : parameters
Connection details
| Name | Description | Flow | Type |
| out | Output | out | d |
Instance parameters
| Name | Description | Type |
| period | Pulse period | real |
| delay | Delay | real |
| duty | Duty cycle | real |
| width | Pulse width | real |
| open_out | Open emitter output | boolean |
Model format
.MODEL model_name d_pulse parameters
Model parameters
| Name | Description | Type | Default | Limits |
| duty | Duty cycle | real | 0.5 | 1e-06 - 0.999999 |
| delay | Initial delay | real | 0 | ???MATH???0 - \infty???MATH??? |
| period | Period. If zero, a single pulse will be output | real | ???MATH???1\mu???MATH???S | 1e-12 ???MATH???- \infty???MATH??? |
| width | Pulse width (overrides duty if specified) | real | period * duty | ???MATH???0 - \infty???MATH??? |
| open_out | Open emitter output | boolean | FALSE | none |
| out_family | See Family parameters | string | UNIV | none |
| out_res | See Output Parameters | real | 100 | ???MATH???0 - \infty???MATH??? |
| out_res_pos | See Output Parameters | real | out_res | ???MATH???0 - \infty???MATH??? |
| out_res_neg | See Output Parameters | out_res | ???MATH???0 - \infty???MATH??? | |
| min_sink | See Output Parameters | real | -0.001 | none |
| max_source | See Output Parameters | real | 0.001 | none |
| vsupply | See vsupply Parameter | real | 5 | none |
Device Operation
This device supplies a repetitive or single pulse of defined period, delay and width. Optionally, the device may be specified to have an open emitter output allowing several pulse sources to be wire OR'ed to create complex pulses. All 5 main .MODEL parameters may also be specified on the device line as instance parameters in which case they override any values specified in the .MODEL statement.
If OPEN_OUT is specified and true, a pull down resistor must be connected to the output.
Digital Signal Source
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 | See Family parameters | string | UNIV | none | |
| out_res | See Output Parameters | real | 100 | ???MATH???0 - \infty???MATH??? | |
| out_res_pos | See Output Parameters | real | out_res | ???MATH???0 - \infty???MATH??? | |
| out_res_neg | See Output Parameters | out_res | ???MATH???0 - \infty???MATH??? | ||
| min_sink | See Output Parameters | real | -0.001 | none | |
| max_source | See Output Parameters | real | 0.001 | none | |
| vsupply | See vsupply Parameter | real | 5 | none |
Device Operation
The digital signal source provides a multi bit arbitrary digital signal defined in a file.
It is the underlying device for the Digital Multi-output Source part available in the schematic editor.
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 or XS | UNKNOWN-STRONG |
| 0R | LOW-RESISTIVE |
| 1R | HIGH-RESISTIVE |
| UR or XR | UNKNOWN-RESISTIVE |
| 0Z | LOW-HI-Z |
| 1Z | HIGH-HI-Z |
| UZ or XZ | UNKNOWN-HI-Z |
| 0U | LOW-UNDETERMINED |
| 1U | HIGH-UNDETERMINED |
| UU or XU | UNKNOWN-UNDETERMINED |
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.
Digital Initial Condition
Netlist entry
Axxxx out model_name
Connection details
| Name | Description | Flow | Type |
| out | Output | out | d |
Model format
.MODEL model_name d_init parameters
Model parameters
| Name | Description | Type | Default | Limits |
| ic | Initial state | integer | 0 | none |
| is | Initial strength 1 = STRONG 0 = RESISTIVE | integer | 1 | none |
| out_family | See Family parameters | string | UNIV | none |
Device Operation
This device has the defined initial state (IC parameter) and initial strength (IS parameter) during the DC operating point solution, then reverts to HI-IMPEDANCE for the remainder of the analysis.
Pulldown Resistor
Netlist entry
Axxxx out model_name
Connection details
| Name | Description | Flow | Type |
| out | Output | out | d |
Model format
.MODEL model_name d_pulldown parameters
Model parameters
| Name | Description | Type | Default | Limits |
| load | Load value (F) | real | 0 | none |
| strong | Strong output | boolean | FALSE | none |
| out_family | See Family parameters | string | UNIV | none |
| state | Output state | string | 0r | none |
| vsupply | See vsupply Parameter | real | 5 | none |
Device Operation
The pulldown resistor provides a single terminal output which defaults to the LOW RESISTIVE state. However, using the STATE parameter it can be set to any of the 12 states supported by the digital simulator as defined in the following table:
| Code | State-Strength |
| 0S | LOW-STRONG |
| 1S | HIGH-STRONG |
| US or XS | UNKNOWN-STRONG |
| 0R | LOW-RESISTIVE |
| 1R | HIGH-RESISTIVE |
| UR or XR | UNKNOWN-RESISTIVE |
| 0Z | LOW-HI-Z |
| 1Z | HIGH-HI-Z |
| UZ or XZ | UNKNOWN-HI-Z |
| 0U | LOW-UNDETERMINED |
| 1U | HIGH-UNDETERMINED |
| UU or XU | UNKNOWN-UNDETERMINED |
Note that if the STATE parameter is present, the STRONG parameter has no effect.
Pullup Resistor
Netlist entry
Axxxx out model_name
Connection details
| Name | Description | Flow | Type |
| out | Output | out | d |
Model format
.MODEL model_name d_pullup parameters
Model parameters
| Name | Description | Type | Default | Limits |
| load | Load value (F) | real | 0 | none |
| strong | Strong output | boolean | FALSE | none |
| out_family | See Family parameters | string | UNIV | none |
| state | Output state | string | 1r | none |
| vsupply | See vsupply Parameter | real | 5 | none |
Device Operation
The pullup resistor provides a single terminal output which defaults to the HIGH RESISTIVE state. However, using the STATE parameter it can be set to any of the 12 states supported by the digital simulator as defined in the following table:
| Code | State-Strength |
| 0S | LOW-STRONG |
| 1S | HIGH-STRONG |
| US or XS | UNKNOWN-STRONG |
| 0R | LOW-RESISTIVE |
| 1R | HIGH-RESISTIVE |
| UR or XR | UNKNOWN-RESISTIVE |
| 0Z | LOW-HI-Z |
| 1Z | HIGH-HI-Z |
| UZ or XZ | UNKNOWN-HI-Z |
| 0U | LOW-UNDETERMINED |
| 1U | HIGH-UNDETERMINED |
| UU or XU | UNKNOWN-UNDETERMINED |
Note that if the STATE parameter is present, the STRONG parameter has no effect.
| ◄ Flip-Flops and Latches | Mixed Signal ▶ |