Can with remapped pins on ch32v203 seems to not work?

[empirephoenix]

Hi,

so glad that canbus is merged:) It works like a charm with the default pins. However since I want to use the usb stuff, I tried to switch it to the secondary pins. This resulted in no output on the pins at all.
Do I need to do more than just switch the pins in the generic? Is there some register for the remapping that I need to poke or should this work automatically?

I tested this with everything unrelated removed so ignore all, except the worker task
https://git.mannheim.ccc.de/C3MA/PlantCtrl/src/branch/goodby-espidf/rust_can_sensor/src/main.rs#L109

[romainreignier]

You might need to add a line to enable the pin remapping like done in this stm32f1 example in embassy.
To be adapted for ch32v.

[empirephoenix]

Thank you for your answer, was not aware of the AFIO, seems that the remapper can be accessed like this with the ch32:
ch32_hal::pac::AFIO.pcfr1().write(|w| w.set_can1_rm(2));
Will test at the end of the week and report back :)

[romainreignier]

The remap seems being done here:

ch32-hal/src/can/can.rs

Lines 226 to 235 in 07687b9

	rx.set_mode_cnf(
	pac::gpio::vals::Mode::INPUT,
	pac::gpio::vals::Cnf::PULL_IN__AF_PUSH_PULL_OUT,
	);
	tx.set_mode_cnf(
	pac::gpio::vals::Mode::OUTPUT_50MHZ,
	pac::gpio::vals::Cnf::PULL_IN__AF_PUSH_PULL_OUT,
	);
	T::set_remap(REMAP);

So maybe we need to add a patch in patches.rs?

Anyway, adding manually the AFIO line in your main might help.

[empirephoenix]

So was able to confirm it with scope and hardware. Adding the second line makes it work, without it it does not seem to work.

    let config = can::can::Config::default();
    let can: Can<'static, CAN1 , Blocking> = Can::new_blocking(p.CAN1, p.PB8, p.PB9, CanFifo::Fifo1, CanMode::Normal, 125_000, config).expect("Valid");
//without out this line it does not work
    ch32_hal::pac::AFIO.pcfr1().write(|w| w.set_can1_rm(2));