LPUART type mismatch & some other issues about UART peripheral implementation

[huming2207]

Hi all,

Sorry for this stupid question, I'm new to Embedded Rust. I'm trying to use this HAL crate with RTIC together to implement a UART-LoRa modem. But so far I just couldn't figure out this issue when I try to enable RXNEIE (receive data register not empty interrupt):

Here's the code: https://github.com/huming2207/lowu-basestation/blob/cdf87dbade6c983cbe4c77556b336dfc17320af9/src/bin/app.rs

I've also tried replacing the uart_p to dp.LPUART but still no luck, and Rust compiler complains the exact same error when compiling so it's not a language server or VSCode plugin's false positive. Anyway, may I ask if is there any suggestion on how to get RXNEIE to be set?

Meanwhile I've also got another issue with defmt-serial earlier in July: gauteh/defmt-serial#1

Basically, the author tested his implementation works fine on some other microcontrollers, but it didn't work at all on my RAK3172 (STM32WLE5JC) development kit. I'm not sure if this issue is related to the USART/LPUART implementation in this crate, but I've brought it here just in case.

Regards,
Jackson

[newAM]

Ouch, that is an unfortunately difficult error message :(

What it is saying is that the closure |_, w| { ... } expects a different return type.

uart_p.cr1.modify(|_, w| {
    w.rxneie().enabled();
});

The semicolon after enabled() makes it look like this to the compiler:

uart_p.cr1.modify(|_, w| {
    w.rxneie().enabled();
    return ();
});

Without the semicolon it compiles:

uart_p.cr1.modify(|_, w| w.rxneie().enabled());

---

For the other issue I'm unfamiliar with defmt-serial, will take a closer look when I have more time this weekend :)

[huming2207]

Ah oops, my bad! 😅 Thanks for your info!

I will have a try again later tonight.

[huming2207]

I can now confirm it's working. Sorry again, I completely misread the error message earlier.

[newAM]

No worries, I've hit that one myself, embedded rust can be difficult at times, happy to help out!