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Showing posts from June, 2024

Setting up vscode+bmp/vscode to debug code in ram (RP2040)

 The main problem when debugging the code in ram is that the CPU will have started to execute whatever is in flash before you catch it, including potentially clearing the ram. As a result , the setup has to be done in 2 steps : - Have a "null" program in flash that does nothing -Tweak a little bit the vscode debug startup sequence Loop in flash The idea here is to modify the very first instruction and replace it with a endless loop. When you use lnArduino that means changing  mcus/arm_rp2040/sdk_copy/crt0.S and replacing the first instruction by       b _entry_point That way, after reset, it will harmelessly loop in the flash. Cortex-debug setup {   "version": "0.2.0", "configurations": [ { "name": "RAM- pico-load", "cwd": "${workspaceFolder}", "svdFile" : "${workspaceRoot}/.vscode/rp2040.svd", "executable": "build/st7789.elf", "gdbPath" : "${co...

CH32V203C8xx : no breakpoint ? :(

 A couple of months back i bought some CH32V203 on ebay.  Why ? They were cheap, they are pin to pin compatible with STM32F103Cxxxx, i can put them on bluepill board . They are fast riscv.  Why not. NB: by mistake i bought the ones with 64kB of flash :( But there is a BIG showstopper, there seems to be no hw breakpoints, only sw breakpoints.  If you have a lot of ram (like the RP2040) you can put the code in ram until it works fine and then put it in flash. That's not the case here. Having the debugger read/modify/write all the time to but sw breakpoint in flash is really a pain. In theory, the "flash" of the CH32 is actually flash copied to ram, so if there was a way to use the fake flash ram to put SW breakpoint in it, we would be good. For reference, the CH32V303 has only 4 breakpoints, and no watchpoint (i.e. triggers with the right capabilities) which is already a bit of a pain in the neck. I'll put those aside for the moment.

lnBMP => Swindle

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In order to avoid confusion , i renamed lnBMP to  swindle   (swindle has SWD in it) It can run on :  GD32F303  CH32V303/5/7 (just need enough flash /ram)  RP2040 (normal or zero) and it can debug all the usual blackmagic targets + CH32V2XX/CH32V3XX. I dropped support for the bluepill / STM32F103 because it has not enough ram/flash and the CH32/GD32/RP are so cheap it is not even worth the time. The next item on my todo list is to update the blackmagic part and to use the PIO controller inside the RP2040 to do SWD / RVSW (Arm/CH32) Example: a itsy bitsy RP2040 zero debugging a CH32V30X based swindle board