general modm interrupt handling examples

[kikass13]

As far as i could tell, there are no common examples for the nucleo and interrupt handling is not documented properly

What should be there

• Proper documentation of interrupt interface via examples
• Proper documentation of which ISR vectors / handlers exist
  • the same way there are typedefs for IOs and common registers via board.hpp, there should be a lookup for possible ISR table entries and their offsets

Examples that should be included

• clean examples of
  • I/O interrupt
  • timer interrupt
  • [dma interrupt (would need a DMA example, if existing)]

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Am I wrong here? What do you guys think

[salkinium]

There currently is no special interrupt API other than the NVIC_* provided by the CMSIS core. Similiarly the MODM_ISR macros are just for convenience. I think that would be the right place to add that you have to manually declare interrupts using MODM_ISR, unless of course the interrupts are used by the modm library (UART or I2C for example). It's currently unclear to a developer which interrupts are used by modm… There's also no protection against misspelling an interrupt handler, so the developer experience is a little miserable.

The modm-devices data does contain the interrupt table, however, it would perhaps be more useful to add the CMSIS header Doxygen documentation to our docs.modm.io generator. I was under the (false) impression that it already was, but I cannot find it anywhere.

[kikass13]

@salkinium at least the enum can be looked up in that header. I wasnt sure where these are defined, some simple examples should help mitigate my confusion. I successfully wrote a button example for the nucleo boards (HURRAY, im god tier now ... :P) because i was unsure about the ethernet stuff not working when using the nucleof439zi

• Are there any plans on extending the interrupts ?
• Should there be a wrapper around the ISR table
  • which would be slower, but would allow to apply interrupts more generic, and also allow multiple interrupt handlers for the same interrupt source)
• are there hardware specific things which would make such a task impossible?
• is this even a modm business to mess with runtime interrupt handling at all?

[salkinium]

Yeah… it's complicated and that's why we haven't made any progress. We have however tried some things, see #307 and #308.

[salkinium]

You can btw remap the vector table to RAM via the :platform:cortex-m:vector_table_location and the use NVIC_SetVector and change whatever you want. Doesn't work on Cortex-M0 though.