We don’t always JTAG, but when we do, we use a Black Magic Probe. It’s a completely open ARM-chip debugging powerhouse. If you program the small ARM chips and you don’t have a BMP, you need a BMP.
If you write code for Linux systems, chances are you will have used the venerable GNU Debugger (GDB). Acting as a back end for many GUIs and the interface to various JTAG debugging tools in the ...