Embedded systems are hard to debug. Complex systems have a lot of variables. When debugging those systems, we often log data into some files, and visualize them later on, using excel, matplotlib or something else. This talk is about tracing and logging. What are the options we have as embedded software developers? I will present the lognplot tool, a project to plot incoming data on the fly. Embedded systems are hard to debug. Complex systems have a lot of variables. When debugging those systems, we often log data into some files, and visualize them later on, using excel, matplotlib or something else. This talk is about tracing and logging. What are the options we have as embedded software developers? I will present the lognplot tool, a project to plot incoming data on the fly. There are two implementations, one in python, and one in rust with gtk-rs. The data is stored internally in a zoomable format, allowing large sets of data to be browsed easily. During the talk you will learn how to draw a chart, and how to aggregate large sets of data into summaries. I will demo a STM32 serial wire viewer output connected to this tool to enable live tracing of an embedded system.