How to support stm32f4 board with less peripherals (e.g. TIM)

[jakub-m]

I want to add support for the stm32f401re Nucleo board. The existing src/machine/machine_stm32f4.go for this family of chips uses definitions for peripherals that do not exist for the stm32f401 family. For example, TIM13:

src/machine/machine_stm32f4.go:278:28: TIM13 not declared by package stm32

Looking at ./src/device/stm32/stm32f401.go I see that there are TIM1 to TIM11.

Question: how to modify machine_stm32f4.go so it is still usable for different chips of stm32f4 family, even those with less peripherals? Should I maybe exclude stm32f401 from machine_stm32f4.go and re-implement everything, or should I make machine_stm32f4.go somehow more generic?

[kenbell]

There's no elegant solution I'm aware of since Go doesn't allow conditional compilation inside a source file.

I think the best thing is to have machine_stm32f4.go only contain the strictly common stuff (so TIM1 through to TIM11), and copy these to both machine_stm32f405.go and machine_stm32f407.go:

• TIM13
• TIM14(?)
• registerUPInterrupt
• registerOCInterrupt

[deadprogram]

I think the request was fulfilled in the new release, so closing. Please reopen if needed. Thanks!

[jakub-m]

Can you direct me to what is actually implemented in the next release? I'd know if I need to implement something on my own or if everything is covered. Thanks!

[aykevl]

I don't think this is "solved" in any way, rather: build tags are the way to go here. It's a bit painful but I think it's the only reasonable option.
In many cases, it's possible to define peripheral implementations in a central file and only list specific instances in chip-specific files. For example, the file machine_nrf528xx.go implements PWM (type PWM) for the chips in the nrf528xx family, and machine_nrf52840.go and machine_nrf52.go use those to define PWM0 etc.

[deadprogram]

Reopening since seems this is a question.