Bus Pirate and Open Logic Sniffer Setup

Bus Pirate and Open Logic Sniffer Setup

In this tutorial we are going to setup the Open Logic Sniffer software and use the Bus Pirate V3 for data capture.

You can watch the video below or follow the steps in the tutorial.


First, download the Open Logic Sniffer software from


Select the zip file option.

The software is written in Java so will work on most operating systems including Linux and Windows. We will be installing it under Windows 7 but other operating systems will be similar. There is no installation program, the files simply need to be extracted from the zip file and placed in a folder.

Create a new folder in c:\program files and call it Open Logic Sniffer or similar and place all the files into it

The program needs to be able to create files itself in this directory, but the default Windows 7 security wont allow it. To fix this, right click the directory and select Properties, Click on the Security Tab and then click the Edit permissions button. Select The Users (yourname)  user and click on the Allow Full control tick box

Windows 7 Security settings

We should be able to run the Logic Sniffer now, so double click the run.bat file to load up the Sniffer software

Assuming all is running, we now need to setup the software for the Bus Pirate board.

Click on Capture / Device and make sure OpenBench LogicSniffer is selected

Open Logic Sniffer Device

Next, click on Capture / Begin capture and the following screen will be displayed

Open Logic Sniffer Connection

Select the Analyzer com port that your Bus Pirate is connected to and make sure Device Type is set to Bus Pirate OLS mode

Next, click on the Acquisition tab and the following page is displayed

Open Logic Sniffer Acquisition

The Bus Pirate V3 can store 4kB of data and can sample at a maximum rate of 1MHz. In this tutorial we are going to analyze an I2C communication at 100kHz so we need to set the speed at a fast enough rate to be able to capture the transitions from high to low and low to high. It is recommended that you choose a sampling rate 10x your communication rate but in reality it can be lower. It is possible to use the maximum sampling rate of 1MHz to analyze I2C running at 400kHz.

For our purposes, we will set the Sampling Rate to 1MHz

Now select the Triggers tab

Open Logic Sniffer Triggers

Click on the Trigger Enabled tick box to turn the triggers on.

At the bottom of this screen you will see Mask / Value tick boxes going from 0 to 31. Our Bus Pirate only has 5 logic inputs so 5 through to 31 are greyed out. Tick in the Mask boxes any inputs that you want a trigger enabled on. Value bits are currently ignored, any change triggers the capture

Now connect up your Bus Pirate to a project using I2C communication. Click on the Capture button and you should see some data similar to that below.

Open Logic Sniffer Data

The top line (channel 0) shows the clock line and the next line (channel 1) shows the data line.

While this is useful, the Logic Sniffer also has a built in Analyzer to analyze and decode the data.

Click on Tools / I2C protocol analyzer

I would suggest that you untick the Detect SDA and SCL as it quite often gets it wrong. You can specify the channels for SDA and SCL and then click on Analyze. You should get results similar to the following

Open Logic Sniffer I2C Analysis

Here you can easily see the data that has been transferred along with the ACK and NACK packets

Click on Close, and back in the main screen you can see the I2C analysis results superimposed onto the data channel

open Logic Sniffer I2C data