PulseView (sigrok)

What PulseView is

PulseView is a Qt-based graphical program for logic analysers, oscilloscopes and mixed-signal instruments, built on the sigrok open source signal analysis libraries. You connect a supported capture device, choose which channels and how fast to sample, record, and then view the signals as waveforms. Its protocol decoders turn those waveforms into meaning: bytes on a UART, addresses and acknowledgements on I2C, frames on SPI, and many more. The sigrok wiki lists 131 supported protocol decoders.

Why every embedded learner should have one

When a sensor returns zeros or a module ignores you, the question is always: what actually went across the wire? Serial prints show what your code thinks happened. A logic analyser shows what did happen: whether the I2C address was sent and acknowledged, whether the SPI clock ran and chip select went low, whether the UART baud rate matches. This single tool turns hours of guessing into minutes of looking.

Hardware you can use

sigrok supports a long list of devices. Many low-cost USB logic analysers are based on the Cypress FX2 chip, and sigrok's open source fx2lafw firmware makes them work as simple logic analysers with PulseView. These inexpensive analysers are widely available and are enough for UART, I2C and typical SPI speeds on hobby and student projects. Check the supported hardware list on the sigrok wiki before buying.

Prerequisites and time

You should know what UART, I2C and SPI are. Installing PulseView, making a first capture of a UART line and adding a decoder takes under an hour. Learn two settings early: sample several times faster than the bus speed, and set a trigger on the first edge so the capture starts at the right moment.

Platforms and releases

The downloads page offers builds for Windows, macOS and Linux (including an AppImage). The latest stable release is 0.4.2, and nightly builds are published with newer fixes.

What you can do with it

• Capture and decode UART, I2C, SPI, 1-Wire, CAN and other buses.
• Measure pulse widths, PWM duty cycles and timing between events.
• Save a known-good capture and compare it with a broken one.
• Include decoded captures in your project write-up as evidence.

Free or paid?

PulseView and sigrok are free and open source under the GPL. You buy only the capture hardware.

Common questions

Is a cheap analyser good enough? For learning and most student projects, yes. Faster or analogue problems need an oscilloscope.

Why does my signal look broken? Usually the sample rate is too low for the bus speed.

Best for: anyone debugging sensors, modules and communication on real hardware.