> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/wokwi/wokwi-docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Logic Analyzer

> 8-Channel Digital Logic Analyzer for capturing and analyzing digital signals

8-Channel Digital Logic Analyzer.

## Pins

Pins D0 to D7 are connected to the input channels of the logic analyzer. There's also a GND pin, which should be connected to the digital ground.

## Attributes

<ParamField path="bufferSize" type="string" default="1000000">
  Maximum number of samples to collect
</ParamField>

<ParamField path="channelNames" type="string" default="D0,D1,D2,D3,D4,D5,D6,D7">
  Comma-separated list of channel names for the VCD file
</ParamField>

<ParamField path="filename" type="string" default="wokwi-logic">
  Name of the recording file, without the extension. The `filename` attribute only applies to the web version. For VS Code, see [vcdFile configuration](/vscode/project-config#logic-analyzer-vcd-export).
</ParamField>

<ParamField path="triggerMode" type="string" default="off">
  Trigger mode: "off", "level" or "edge"
</ParamField>

<ParamField path="triggerLevel" type="string" default="high">
  "high" or "low"
</ParamField>

<ParamField path="triggerPin" type="string" default="D7">
  "D0" … "D7"
</ParamField>

## Sample buffer

The logic analyzer uses a buffer to store the recorded pin data. Each pin level change (e.g. low to high) occupies one slot in the buffer. The simulator allocates the memory for the buffer in advance, to ensure fast simulation.

You can choose the size of the buffer by setting the `bufferSize` attribute. Each slot in the buffer uses 9 bytes of RAM. Thus, the default buffer size of 1 million samples will use about 9 MB of RAM. Allocating a large buffer may strain your browser.

The logic analyzer displays the number of samples captured while the simulation is running. You can use this number to estimate the required buffer size.

## Trigger

The trigger controls when the logic analyzer starts recording data. By default, the trigger is off, so the logic analyzer captures all the data. You can configure the trigger using three attributes `triggerMode`, `triggerPin` and `triggerEdge`.

The following table summarizes the available trigger modes:

| triggerMode | Description     | Behavior                                                |
| ----------- | --------------- | ------------------------------------------------------- |
| "off"       | Disable trigger | All data is recorded                                    |
| "edge"      | Edge trigger    | Start recording when `triggerPin` equals `triggerLevel` |
| "level"     | Level trigger   | Record only while `triggerPin` equals `triggerLevel`    |

The "edge" mode starts recording when the `triggerPin` changes to `triggerLevel`, and continues recording until the simulation terminates. For example, if you set `triggerPin` to "D7" and `triggerLevel` to "high" (their default values), the logic analyzer will start recording when pin D7 goes high.

The "level" mode is more versatile: just like the "edge" mode, it starts recording when the `triggerPin` changes to `triggerLevel`, but it will pause the recording as soon as `triggerPin` changes again.

For usage examples, check out the [Using the Trigger section](/guides/logic-analyzer#using-the-trigger) in the Logic Analyzer Guide.

## Viewing the data

When you stop the simulation, the logic analyzer saves the recorded samples to a file. The recording file uses the standard [Value Change Dump (VCD)](https://en.wikipedia.org/wiki/Value_change_dump) format.

In the web version, the file is downloaded to your computer as "wokwi-logic.vcd" by default (configurable via the `filename` attribute). In VS Code, the file is saved as "wokwi.vcd" in your project root (configurable via [vcdFile](/vscode/project-config#logic-analyzer-vcd-export)).

To learn how to view the data, please visit our [Logic Analyzer Guide](/guides/logic-analyzer#using-the-logic-analyzer).

## Simulator examples

* [Logic Analyzer recording I2C protocol signals](https://wokwi.com/projects/325933824665977428)