16:28 <re_irc> <@yruama_lairba:matrix.org> ;( i'm stuck on a dma issue

16:31 <re_irc> <@yruama_lairba:matrix.org> i don't understance what happen but my dma transfert don't want to run. when i set the "en" bit, i laways get the disabled value when reading it back

16:32 <re_irc> <@yruama_lairba:matrix.org> it soo much anoying because i just took a code that was working and adapted for RTIC context

16:49 <re_irc> <@korken89:matrix.org> yruama_lairba:matrix.org: If you have the code to share I'd take a look :)

16:49 <re_irc> <@korken89:matrix.org> yruama_lairba:matrix.org: There is quite a good one in stm32l4xx hal

16:51 <re_irc> <@yruama_lairba:matrix.org> korken89: i'm using stm32f4 chip and i'm bypassing the stm32f4xx hal

16:51 <re_irc> <@korken89:matrix.org> Well you can copy the implementation then

16:51 <re_irc> <@korken89:matrix.org> So you don't walk in the same pitfalls :)

16:52 <re_irc> <@yruama_lairba:matrix.org> i'm not sure a generic hal can be used for what i want to do

16:53 <re_irc> <@riskable:matrix.org> A friend of mine wants to customize and run my keyboard firmware but he's not the type that would have an easy time setting up a Rust build environment for embedded use... Is there a service that can build a firmware from a Github repo? If not I'll stand one up

16:53 <re_irc> <@yruama_lairba:matrix.org> i want to use 2 dma stream in circular mode and on the same buffer

16:54 <re_irc> <@korken89:matrix.org> It all depends on what you want to do, plus seeing how the DMA used is used may help you find issues with your implementation

16:54 <re_irc> <@newam:matrix.org> riskable:matrix.org: github actions can do exactly that :)

16:54 <re_irc> <@riskable:matrix.org> newam:matrix.org: Yeah I figured there'd be something like that already

17:01 <re_irc> <@yruama_lairba:matrix.org> korken89: here it is https://github.com/YruamaLairba/nucleo64-guitar-dsp-firmware/tree/dma

17:01 <re_irc> <@yruama_lairba:matrix.org> but there is many line of code

17:02 <re_irc> <@yruama_lairba:matrix.org> and many unsafty :p

17:15 <re_irc> <@yruama_lairba:matrix.org> korken89: does my code too ugly to be read by somone else ? ;)

17:42 <re_irc> <@korken89:matrix.org> yruama_lairba:matrix.org: I had a look, but it's too mixed together for me to make sense of it

18:43 <re_irc> <@yruama_lairba:matrix.org> lol, this is what i feared

18:43 <re_irc> <@yruama_lairba:matrix.org> unfortunatly, i don't know how to make it mor clear

18:52 <re_irc> <@yruama_lairba:matrix.org> i guess i should go back to something that work and implement dma separately

18:54 <re_irc> <@therealprof:matrix.org> yruama_lairba: I'd probably look at DMA once there're no more options to do what needs doing without.

18:59 <re_irc> <@yruama_lairba:matrix.org> therealprof: ok, i want to use it for optimization, mainly by reducing context switching

19:02 <re_irc> <@yruama_lairba:matrix.org> i didn't made measurement, but i think it worth to reduce by ~100 the number of triggered interuption

19:05 <re_irc> <@yruama_lairba:matrix.org> expecially when initially i have 48 000*4 interruptions during normal operation

19:13 <re_irc> <@therealprof:matrix.org> Do you need to reduce the amount of interrupts?

19:37 <re_irc> <@yruama_lairba:matrix.org> therealprof: i want to reduce the penalty due to interrupts execution

20:01 <re_irc> <@yruama_lairba:matrix.org> i wonder how i could determine the average cpu cycle to fully execute my interrupt

20:06 <re_irc> <@newam:matrix.org> yruama_lairba:matrix.org: it depends on what features your CPU has. ARM CPUs have a trace peripheral included with the core for measuring things like this.

20:07 <re_irc> <@yruama_lairba:matrix.org> newam: have you a doc for it ?

20:09 <re_irc> <@newam:matrix.org> Depends on your core. If you do have an ARM core you'll want to look at the ARMvX-M architecture reference manual (you probably want v6 or v7).

20:09 <re_irc> <@newam:matrix.org> This is for v7: https://developer.arm.com/documentation/ddi0403/latest

20:10 <re_irc> <@yruama_lairba:matrix.org> I think the arm i use is a cortex m4

20:10 <re_irc> <@newam:matrix.org> Yup, that's v7

20:12 <re_irc> <@newam:matrix.org> A simple place to start is the cycle counter. Literally counts CPU cycles, you sample it twice, compare the difference. The name is DWT.CCNT or something like that.

20:12 <re_irc> <@newam:matrix.org> There are more advanced features, but they take time to setup.

20:14 <re_irc> <@yruama_lairba:matrix.org> ok, i just need to count cpu cycle

20:16 <re_irc> <@yruama_lairba:matrix.org> thanks to gave me DWT.CCNT because the arm doc difficult to understand

20:18 <re_irc> <@newam:matrix.org> ```rs

20:18 <re_irc> ... long message truncated: https://psion.agg.io/_matrix/media/r0/download/psion.agg.io/a6ea5c97379abdf44578ae6e03c05f54204c2a247dbb94158e7af400418c1a52 (7 lines)

20:18 <re_irc> <@newam:matrix.org> use cortex_m::peripheral::{Peripherals, DWT};

20:18 <re_irc> <@newam:matrix.org> peripherals.DWT.enable_cycle_counter();

20:18 <re_irc> <@newam:matrix.org> let mut peripherals = Peripherals::take().unwrap();

20:18 <re_irc> <@yruama_lairba:matrix.org> DCB.enable_trace() ? it's required ?

20:19 <re_irc> <@newam:matrix.org> Yup. Most of the time you don't want to spend the power to keep debug features enabled (for release firmware)

20:21 <re_irc> <@yruama_lairba:matrix.org> will do that later

22:04 <re_irc> <@yruama_lairba:matrix.org> newam: your code deosn't work here, i don't know how to get CorePeripherl from rtic context

22:05 <re_irc> <@yruama_lairba:matrix.org> i tried use the unsafe `stm32::DCB::ptr()` but `enable_trace()` is not defined ???

22:36 <re_irc> <@grantm11235:matrix.org> I think you need to dereference the pointer. Try `unsafe {*(stm32::DCB::ptr()).enable_trace()}`

22:49 <re_irc> <@yruama_lairba:matrix.org> i finally got it from rtic, i was context.core.DCB

22:50 <re_irc> <@yruama_lairba:matrix.org> and i did my measure, execution of my interrupt is 100~200 cpu cycle

22:52 <re_irc> <@yruama_lairba:matrix.org> this is almost ten time more than i expect

22:57 <re_irc> <@yruama_lairba:matrix.org> if i calculate correctly, i spend 20~40% of cpu time inside my interruption

23:01 <re_irc> <@yruama_lairba:matrix.org> so it really worth to use dma to handle I2S transfer

23:09 <re_irc> <@yruama_lairba:matrix.org> with dma, i estimate less than 0.1% time spended in interuption to handle the same transfer