Marker trait to allow blocking API

[adejewski]

Hi @gauteh ,

I got a question. I am working with STM32WL and I am using new embedded_hal v2. According to defmt-serial you need to use blocking API, but the embedded_hal in this version does not provide it. How to implement this marker trait Default to enable it?

The code blow shows, how I tried to use it:

  let uart: LpUart<pins::A3, pins::A2> = cortex_m::interrupt::free(|cs| {
        LpUart::new(dp.LPUART, 115_200, uart::Clk::Hsi16, &mut dp.RCC)
            .enable_rx(gpioa.a3, cs)
            .enable_tx(gpioa.a2, cs)
    });

    defmt_serial::defmt_serial(uart);

[gauteh]

Here is how I did it for ambiq hal: https://github.com/gauteh/ambiq-rs/commit/a9bdbb5c7cfae0cece923872a29e1421a9b03696

impl hal::blocking::serial::write::Default<u8> for Uart0 {}

[adejewski]

Anyway, used your code as an example and implemented my own version that accepts non-blocking version of write. It works as expected :) Thanks

[gauteh]

By the way, issue #1 is also related to STM32WL. Maybe this works now?

[adejewski]

Not sure what the other issue is about, but for me the biggest problem was not the code, but how to read the data. It took me some time before I realized you need this defmt-print application to decode the log. I know that you are mentioning it in readme, but might be also worth adding there a full command how to redirect logs using socat to defmt-print.

[gauteh]

Yeah, agreed. Just hasn't gotten around to it. Feel free to add some suggestion.

[adejewski]

Will create a PR to the readme file to explain how to decode the logs on linux system, give me a couple of days