00:00 <re_irc> <chrysn (@chrysn:matrix.org)> Is there, when building a static library with no_std, any difference between panic=abort and the default panic=unwind?

00:03 <re_irc> <chrysn (@chrysn:matrix.org)> I found none when building for typical embedded targets, but some difference when building for i686-unknown-linux-gnu (but maybe it's just ordering of text sections)

00:03 <re_irc> <chrysn (@chrysn:matrix.org)> A relatively annoying difference is that I have to set an "eh_personality" -- even though it's not used; is this really necessary?

02:39 <re_irc> <justacec> I have been trying to figure out how to use DMA with a UART inside the stm32wlxx_hal. Specifically, I am unclear how to set the memory address. I see there are some traits defined as DmaOps, but not sure how to access them. Does anybody here have any experience with this?

02:39 <re_irc> <justacec> Maybe has some sort of example I can look through to better understand

09:16 <re_irc> <therealprof> thejpster: Nope, but thanks for the pointer. I'm fully immersed in neovim, it's brilliant but it takes a long time to figure out all the configuration required to get all the bells and whistles.

09:21 <re_irc> <ryan-summers> Have you ever figured out how to get rust-analyzer to do derive macro expansion in neovim? I got the analyzer running, but can't figure out the commands to do macro expansion...

09:27 <re_irc> <therealprof> I haven't tried. Let me see.

09:37 <re_irc> <therealprof> "RustExpandMacro" from https://github.com/simrat39/rust-tools.nvim seems to work for me.

09:51 <re_irc> <therealprof> https://psion.agg.io/_matrix/media/r0/download/matrix.org/cfLctTdNwSusicjlyqUUDIvT/Screenshot%202022-03-09%20at%2010.51.01.png

09:56 <re_irc> <ryan-summers> Hmm, that looks quite interesting. I've been wanting to do expansion on some proc-macros and all the people working in VSCode have been bragging about the macro expansions there

10:09 <re_irc> <ryan-summers> Ooh that works like a charm. Thanks for the hint

10:28 <re_irc> <wilsk> 👋 I've got a USB HID device thats working on an STM32F103 (blue pill) and a custom STM32F042 board. Its kind of like a custom mini macro keyboard using usbd-hid. I've noticed that as soon as I enable another timer (for instance TIM2 on the STM32F103) following any of the timer examples, the USB device is no longer recognised.

10:29 <re_irc> <wilsk> 👋 I've got a USB HID device thats working on an STM32F103 (blue pill) and a custom STM32F042 board. Its kind of like a custom mini macro keyboard using usbd-hid. I've noticed that as soon as I enable another timer (for instance TIM2 on the STM32F103) following any of the timer examples, the USB device is no longer recognised. Any hints on what I'm doing wrong here? I can't find any examples of both USB and a timer to...

10:29 <re_irc> ... follow.

10:31 <re_irc> <wilsk> The timer is set up like this

10:31 <re_irc> let mut timer = dp.TIM2.counter_hz(&clocks);

10:31 <re_irc> timer.start(Hertz::Hz(5)).ok();

10:31 <re_irc> timer.listen(Event::Update);

10:31 <re_irc> ... long message truncated: https://psion.agg.io/_matrix/media/r0/download/psion.agg.io/005f4fc65a52b7e6a2371cb8da10932cf0e660d3923b27ae4ca78c73de927fc2 (10 lines)

10:31 <re_irc> <wilsk> https://github.com/will-hart/pedalrs/blob/periodic_reporting/src/configure/stm32f103.rs#L66

10:35 <re_irc> <ryan-summers> Are you clearing the interrupt flag in your handler? You might be sitting in the ISR handler re-entering and not servicing the USB interface

10:38 <re_irc> <wilsk> I suspected something like that but the only time I'm touching interrupts in this case is the "NVIC::unmask()" call on line 5 above. Should I explicitly unmask the USB interrupts as well?

10:47 <re_irc> <ryan-summers> No, I mean when an interrupt occurs, there's a flag that occurs in the timer registers that has to be cleared

10:50 <re_irc> <ryan-summers> The UIF bit of the TIM SR register has to be cleared

10:50 <re_irc> <wilsk> ah ok, sorry this is my first STM32 project :) Thanks - I'll look into that

11:03 <re_irc> <wilsk> Success!! That worked thanks ryan-summers. Would I usually find this kind of thing documented in the application notes? The STM32 datasheets are quite light on

11:03 <re_irc> <ryan-summers> This is more a "many years of working on embedded projects" kind of thing

11:03 <re_irc> <ryan-summers> Generally, never assume IFG flags are auto-cleared unless docs tell you they are explicitly

11:08 <re_irc> <wilsk> Interestingly the stm32f0xx-hal crate doesn't have the "clear_interrupt" option but at least I know what to look for now! Thanks!

11:11 <re_irc> <adamgreig> wilsk: have you got the "reference manual" open, as well as the datasheet? that's where this stuff is documented

11:12 <re_irc> <adamgreig> (though still not very explicitly - there's no little callout saying "be sure to clear uif" or anything...)

11:13 <re_irc> <wilsk> thanks, will get that one open as well 👍️

11:19 <re_irc> <wilsk> +Edit: ahhhh 2200 pages of manuals, thats more like it 😆

14:28 <re_irc> extern "C" {

14:28 <re_irc> <diondokter> Does anybody know what's going wrong here?

14:28 <re_irc> static mut __ebss: u32;

14:28 <re_irc> static mut __sbss: u32;

14:28 <re_irc> ... long message truncated: https://psion.agg.io/_matrix/media/r0/download/psion.agg.io/0aa4856b49133c1c7154819ab00dced0b73472c96a78e35cf70804dd0f7dd9ed (12 lines)

14:32 <re_irc> let start = &__sbss as *const u32 as u32;

14:32 <re_irc> <diondokter> Ah, found it! It has to be

14:32 <re_irc> There's an extra "&" in there

14:32 <re_irc> <xiretza> right, those linker symbols are really only useful for their addresses, not their values

14:33 <re_irc> <diondokter> Yep

14:34 <re_irc> <diondokter> It's not the value you need, but the address of the variable itself.

14:34 <re_irc> So, take a reference to it, cast that to a pointer and cast that to an integer to 'get the value'

17:32 <re_irc> <chrysn (@chrysn:matrix.org)> Rust currently has a stabilization streak for things I've been using in embedded projects -- with 1.59 it's asm (allowing the bulk of examples), with 1.60 it'll be cfg(panic) (easing stable builds of examples that share code with native) and with 1.61 const_fn_trait_bound and const_fn_fn_ptr_basics (allowing things in flash that would otherwise have needed lazy initializers so ugly I rather went for...

17:32 <re_irc> ... nightly)

17:32 <re_irc> <chrysn (@chrysn:matrix.org)> Keep it going! :-)

21:02 <re_irc> <corecode> korken89: i'm trying to prototype a state machine library, more closely oriented to UML, would be good to get your input, but I'm still stuck at the early stages

22:40 <re_irc> <firefrommoonlight> diondokter: These pointer operations feel like magical incantations you memorize

22:40 <re_irc> <firefrommoonlight> See also: various combinations of "Arc", "Rc", "RefCell", "Mutex"

22:41 <re_irc> <firefrommoonlight> These pointer operations feel like occult incantations you memorize