Does not handle attiny412 TCA0 possibly due to split mode

[APan55555]

When I run atdf2svd for the attiny412, the following warnings appear:

Warning: Unhandled register node: "<register-group name-in-module=\"TCA_SINGLE\" offset=\"0\" name=\"SINGLE\" union-tag-value=\"0\" ...>"
Warning: Unhandled register node: "<register-group union-tag-value=\"1\" name-in-module=\"TCA_SPLIT\" name=\"SPLIT\" offset=\"0\" ...>"
Warning: Merging interrupt TCA0_LUNF and TCA0_OVF to TCA0_LUNF_OVF
Warning: Merging interrupt TCA0_LCMP0 and TCA0_CMP0 to TCA0_LCMP0_CMP0
Warning: Merging interrupt TCA0_CMP1 and TCA0_LCMP1 to TCA0_CMP1_LCMP1
Warning: Merging interrupt TCA0_CMP2 and TCA0_LCMP2 to TCA0_CMP2_LCMP2
Warning: No registers found for peripheral "TCA0"

These are omitting the ones regarding no field description. The svd file generated doesn't have the TCA0 peripheral as a result.

I suspect this is due to the split mode of the peripheral resulting in register blocks that overlap in the atdf (one for the single mode and one for the split mode) that the program doesn't know how to handle.

Adding support for this would be great!

[Rahix]

I think this was also discussed a bit in #4 already. The problem is that there isn't really a way to represent this well in SVD...

[APan55555]

Ok thanks! Are there any recommended resources to see how to add code for the peripheral after running svd2rust?

[Rahix]

Are there any recommended resources to see how to add code for the peripheral after running svd2rust?

We don't do that, everything has to be emitted by svd2rust correctly... Otherwise, maintaining the PACs would be a nightmare.

So the correct course of action is:

1. Find out how the peripheral should be presented in SVD
2. Ensure we're not totally violating the spec with that
3. Talk to svd2rust upstream to see what they think about the issue
4. Implement support in svd2rust and atdf2svd

[Rahix]

As a pointer, there is an alternateRegister in the SVD standard: https://www.keil.com/pack/doc/CMSIS/SVD/html/elem_registers.html Maybe this is what we need here.

[ansemjo]

I wanted to quickly chime in here, as I think my issue is related: on an ATtiny414 there is currently no TCA0 in the avr_device::attiny414::Peripherals (with avr_device v0.8.1). So I think, this still needs #4 to be properly fixed.

[Rahix]

Interesting. Can you check if #79 solves this for you, then?

[ansemjo]

Yes, I think it does:

I cloned https://github.com/Rahix/avr-device locally and edited the Cargo.toml to use that PR and ran cargo build --features attiny414,rt:

 [build-dependencies]
-atdf2svd = { version = "=0.5.1", default-features = false }
+atdf2svd = { git = "https://github.com/Rahix/atdf2svd", rev = "refs/pull/79/head", default-features = false }

Then in my own project, I used that local path in my dependencies:

[dependencies]
#avr-device = { version = "0.8.1", features = [ "attiny414", "rt" ] }
avr-device = { path = "/tmp/tmpdir-m0noK2/avr-device", features = [ "attiny414", "rt" ] }

I haven't actually tried using it yet but it looks promising.

Can confirm, that I can set a prescaler on TCA0, enable it and use it as a clock source on TCB0. Haven't tried to use the split mode yet.

// configure clock prescaler on TCA0: 10 MHz / 1024 ~ 10 kHz
TCA0.single().ctrla().write(|w| w.enable().set_bit().clksel().div1024());

// configure timer B for periodic interrupt at roughly 1 Hz
TCB0.ccmp().write(|w| w.set(10_000));
TCB0.intctrl().write(|w| w.capt().set_bit()); // enable interrupt
TCB0.ctrla().modify(|_, w| w.enable().set_bit().clksel().clktca()); // enable timer

[Rahix]

Alright, thanks a lot for the feedback. I'll try to get that PR merged soon.