OpenOCD skill for embedded hardware debugging. Use when configuring OpenOCD for JTAG or SWD targets, flashing firmware, connecting GDB to bare-metal targets, setting hardware watchpoints, or using J-Link with OpenOCD. Activates on queries about OpenOCD, JTAG, SWD, GDB remote target, flash programmin

OpenOCD / JTAG Debugging Purpose Guide agents through configuring OpenOCD for JTAG and SWD targets, flashing firmware to microcontrollers, attaching GDB for bare metal debugging, setting hardware watchpoints, and configuring J Link and CMSIS DAP adapters. Triggers "How do I connect GDB to my MCU with OpenOCD?" "How do I flash firmware using OpenOCD?" "How do I set up J Link with OpenOCD?" "What's the difference between JTAG and SWD?" "How do I set a hardware watchpoint in GDB?" "OpenOCD says 'Error: unable to find JTAG device' — how do I fix it?" Workflow 1. JTAG vs SWD Feature JTAG SWD (Serial Wire Debug) Pins 4+ (TCK, TMS, TDI, TDO, TRST) 2 (SWCLK, SWDIO) Multi target Yes (daisy chain) No (one target) Speed Up to 30 MHz Up to 10 MHz Availability Full JTAG: Cortex A/R, RISC V SWD: Cortex M only Cable cost More complex Simpler 2 wire Most Cortex M microcontrollers support both. Use SWD when pin count is limited. 2. OpenOCD configuration 3. Connecting GDB 4. Flashing firmware 5. Hardware breakpoints and watchpoints Software breakpoints ( break ) patch instruction memory with trap instructions — they don't work in flash execute in place without debug registers. Use hardware breakpoints instead: 6. OpenOCD commands reference 7. Common errors Error Cause Fix unable to find JTAG device Wrong interface, cable, or power Check USB connection; power target; verify interface config JTAG scan chain interrogation failed Wrong target config or bad SWD mode Match config to exact MCU; try transport select swd flash 'stm32f4x' is not supported Wrong target Check MCU part number; use correct .cfg Error: timed out while waiting for target halted Target running, not halted monitor halt ; check BOOT pins Cannot access memory at address MMU, memory protection, or wrong address Check MPU config; use correct flash/RAM address Warn: target not examined yet OpenOCD not connected to target Check power and connections 8. J Link configuration J Link GDB Server (alternative to OpenOCD): Related skills Use skills/embedded/freertos for FreeRTOS aware debugging with OpenOCD Use skills/embedded/zephyr for Zephyr's west debug integration Use skills/debuggers/gdb for GDB session management Use skills/embedded/linker scripts for understanding memory map for flash addresses

openocd-jtag