Thanks for this, definitely helpful! The 24-bit instructions with 32-bit word access really make for some gotchas.ĭo you have any clues how software breakpoints like these interact with the IRAM caching? Does anyone know how the cache is mapped to flash, is it as simple as 'the first 32kb of SPI flash is cached' or are there cache lines? Wed 12:59 am #11236 uzevla wrote:Hi, for setting the breakpoints, hopefully this code might help you. Memcpy((wrbuf + skip), breakpoint, size) * Save memory to provided location, save BP as well for comparison when unplanting * Write BP address (aligned to 4-bytes because IRAM is accessible wi) */ UCHAR* breakpoint = (size = 2) ? DENSITY_LITTLE_BREAKPOINT: LITTLE_BREAKPOINT UINT32 wrbuf // temp var used to read and write memory to be 8+3 bytes so it stores 2-words read out + breakpoint. saved_data points to the location in your BP array. Void set_bp(UINT32 addr, INT size, UCHAR* saved_data) JTAG Signal -> ESP8266 GPIO Pin -> JTAG Pin (standard 20 pin connector)Ĭode: Select all #define LITTLE_BREAKPOINT.I think it may be possible to use modules without exposed RESET, provided you don't configure those pins as GPIOs in your program(?) I've only used an ESP-12 module as it has an exposed RESET line. (Note: at this stage un-detailed bug reports like 'it doesn't work' aren't helpful, sorry, it doesn't work particularly well for anyone right now. Help wanted! Anyone who can help debug problems or finish things off is very welcome!! EDIT: This bug is fixed, gdb seems stable now >There's currently a bug that causes it to lose sync randomly after a short time and requires a reset. gdb kind of works - using the gdb built from the esp8266 crosstool-ng fork can attach, halt, step, view register state and assembly dump, etc.Can read and write memory and registers.Can connect, halt, resume and single step instructions.

Still very early days, not quite usable as a JTAG debugger yet but I think we will get there. Mostly this means adding Xtensa architecture support, or at least enough that esp8266 can work. I've been working on adding esp8266 support to the openocd open source debugger program.

Openocd jtag