Hi all,
After a few years of toying around with AVR I started experimenting with
ARM using libopencm3. I got myself a cheap STM32 board and started coding.
I was trying to get a very simple example working using a timer, ISR and a
LED connected to a PWM port, and spent many hours not getting it to work.
I've tried to adopt the example in
'libopencm3-examples/examples/stm32/f1/other/timer_interrupt' to my
specific board using different GPIO and Maple's linker script, but no luck
too.
I've narrowed the code down to something that should toggle the onboard LED
at 2Hz, yielding a 1Hz LED blinker. Unfortunately, the LED is shut off
after the bootloader (Maple's DFU) finishes.
I've created a Gist with my files:
https://gist.github.com/jonkerj/e40e9b95f8e336c26a23
I am not an expert on vector tables, but I find the generated vector table
in my ELF binary rather suspicious for two reasons.
First of all, I am trying to hook on TIM2's IRQ, which should be IRQ 28 on
STM32 F1, according to ST's datasheet and libopencm3's json file. If we
take a look into the objdump in the gist, we see that the vector table
starts at 0x8005000. My ISR seems to be referenced at 0x80050b0 (that's IRQ
44, right?) and not at 0x8005070 (which is IRQ 28).
Secondly, the vector table references the ISR routine "off by one": my ISR
starts at 0x080051cc and the vector table jumps to 080051cd.
I am a bit at loss if I am messing things up or if I'm running into a bug,
so I was hoping a post to libopencm3's list could shed some light on this
matter.
Best regards,
Jorik Jonker
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