Circuitpython NRF memory allocation notes

Links:

gc_activity.md (primary how-to guide)

output_gc_until_repl.txt 

https://hackaday.io/project/86818-game-turbo/log/146645-debugging-circuitpython

https://gnu-mcu-eclipse.github.io/debug/jlink/install/

https://devzone.nordicsemi.com/f/nordic-q-a/46383/nrf52840-dk-onboard-segger-j-link

 


NRF52 Dongle USB Segger Setup on Linux
Install USB extensions for VirtualBox

Passthrough USB Dongle (labeled “Segger”)

Goto https://www.segger.com/downloads/jlink?step=1&file=JLink_510d#J-LinkSoftwareAndDocumentationPack and download “J-Link Software and Documentation pack for Linux, DEB installer, 64-bit”

sudo dpkg -i JLink_Linux_x86_64.deb

Test function: nrfjprog -f nrf52 --reset


Debugging Steps (heap analysis)

Setup SWD and run GDB
Connect SWD debugger (NRF52 dongle appears to work)

cd circuitpython/ports/nrf

Uncomment “#define LOG_HEAP_ACTIVITY 1” in circuitpython/py/gc.c

append ‘-ggdb’ to CFLAGS in ports/nrf/mpconfigport.mk

Add `_rom_start = ${CIRCUITPY_FIRMWARE_START_ADDR};` to /ports/nrf/boards/common.template.ld

Adjust the following two lines in analyze_heap_dump.py
-    rom_start = symbols["_sfixed"][0]
-    ram_start = symbols["_srelocate"][0]
+    rom_start = symbols["_rom_start"][0]
+    ram_start = symbols["_ram_start"][0]



make -j10 BOARD=feather_nrf52840_express

Flash board with new UF2

Optional: add “set breakpoint pending off” to gdb run script

Disconnect USB to PC or there will be a breakpoint resource issue with gdb

Start GDB server in another console: JLinkGDBServer -if SWD -device nRF52840_xxAA

uncomment and adjust append line to ‘append binary memory ram.bin &_ram_start &_estack’

arm-none-eabi-gdb -x ../../tools/output_gc_until_repl.txt build-feather_nrf52840_express/firmware.elf


Processing memory output
python3 ../../tools/gc_activity_between_collects.py mylog.txt


Create Visual Outputs
sudo apt-get update

sudo apt-get install python3-setuptools

pip install wheel
sudo apt-get install python3-dev graphviz libgraphviz-dev pkg-config

pip3 install click

pip3 install graphviz

pip3 install pygraphviz

mkdir heapviz

python3 ../../tools/analyze_heap_dump.py ram.bin build-feather_nrf52840_express/firmware.bin build-feather_nrf52840_express/firmware.elf.map --print-heap-structure --draw-heap-ownership