Logic Analyzer Overview

Today I will introduce you a powerful tool to capture, decode and analyze digital signal in embedded system – Logic Analyzer

1. Why do we need logic analyzer?

Transmission protocols as UART, SPI, I2C, I2S, USB, CAN … always exist as indispensable part in embedded system.

And these protocol always have the transmitter and receiver working with digital signal between them.


Now I assume that we need to check a protocol and make sure it works. We send data as a message from transmitter and expect these data is save correctly by receiver. Unfortunately, this system has problem and you got nothing from receiver. What could be the reason?

  • The transmitter is sending data or not
  • The transmitted data has right format or not
  • Every data channel is working or not
  • The receiver send ACK packet or not

We can not seat and guess which one is correct in a bunch of reasons, we need a tool to analyze the digital signal is transmitted then conclude the final reason. For example:

  • If the tool receive nothing, that means transmitter is not sending anything
  • If the tool is receiving data, but the format does not match to protocol format, that means transmitter has problems
  • If everything is correct, we have to check the operation inside receiver

Logic Analyzer was born to solve this problems for us. This powerful tool has ability to capture, decode and analyze digital signal by well known protocol, and our works become much easier.

2. Logic Analyzer installation

  • There are several types of logic analyzer, with different information about supported trigger speed and number of channels. However you don’t need to worry, USB Logic Analyzer 24M 8CH is enough for us and you can buy it very easily nowadays.
  • This device need application on PC to run and display analyzer monitor. Follow this link and you can download it https://www.saleae.com/downloads/
  • Run downloaded Logic Setup 1.2.18.exe file to install Window application like other software
  • Access installed software

3. User’s Guide

You can find detail support information in https://support.saleae.com/user-guide/using-logic , about the important part:

  • Connecting the Logic Hardware
  • Logic Accessories
  • Using the Trigger

In next post, I will show you how to use our device in real world. See you soon.

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