The "Black Magic Probe" is a debug probe for ARM Cortex micro-controllers, supporting SWD and JTAG. What sets it apart from other debug probes is that it directly supports the Remote Server Protocol of GDB (also used by LLDB and other debugging and development tools). This quashes the need for additional middleware, services or drivers, and thereby makes the software/hardware toolchain simpler, more portable and more reliable. What you can do with the Black Magic Probe is: ¿ Download code into Flash ROM or RAM of the micro-controller. ¿ Step through code, look at a backtrace of the call stack. ¿ Set up to six hardware breakpoints and up to four hardware watchpoints (unlimited software breakpoints). ¿ Inspect and modify variables, memory and registers. ¿ Run the code and follow it with real-time tracing. The Black Magic Probe is an open-source project, in both its hardware design and its software. Various derivatives have appeared, some with added features, some as low-cost variants of the original. This book focuses on the original Black Magic Probe, but it also covers the ctxLink probe - an enhanced design that offers truly remote debugging, due to its Wi-Fi connection and rechargeable battery.