Add blackpill+PCM5102A example

[elagil]

Create firmware for Blackpill + PCM5102A DAC, based on blus_mini_mk1

[litezxc]

I can write hse and other parameters for 0% errors on 48khz
32-bit: 384 5 12 1 48000 0.0000%
RCC_OscInitStruct.PLL.PLLM = 25;
RCC_OscInitStruct.PLL.PLLN = 336;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
RCC_OscInitStruct.PLL.PLLQ = 7;
PeriphClkInitStruct.PLLI2S.PLLI2SN = 384;
PeriphClkInitStruct.PLLI2S.PLLI2SR = 5;

[elagil]

That will help with the setup. What pins for I2S do you use?

[litezxc]

V5+ VIN
GND GND
B12 (i2s2_ws) LCK
B15 (i2s2_sd) DIN
B10 (i2s2_ck) BCK
GND SCK

[elagil]

Please extract and flash. I hope it shows up on USB.
This is an elf file.

blackpill_pcm5102a.zip

[litezxc]

one sec

[litezxc]

[elagil]

I guess you need a bin file then, not an elf?

[litezxc]

may be:)

[elagil]

Let's try ;)
firmware.bin.zip

[litezxc]

yes, sir!

[litezxc]

[elagil]

Do you have a field to enter it?

[litezxc]

what is it? :)

[elagil]

I think 0x08000000

[litezxc]

maybe hex file?

[elagil]

What do you mean? Do you not have a field for the start address?

[litezxc]

[elagil]

Use "Start address"

[litezxc]

How? Im sorry Im stupid 🥇

[elagil]

Below file path, there is a start address field. You just enter 0x08000000 in it

[litezxc]

Device did not show up

[elagil]

Did you disconnect/reconnect usb? That might be necessary.

[litezxc]

Yes

[elagil]

I will check what might be wrong, probably some clock setting

[elagil]

Ok, maybe this one. Disables VBUS detection. It might not be present on your device.

firmware.bin.zip

[litezxc]

If a reason is found, then that project might also work 💯

[litezxc]

No device

[litezxc]

Maybe there is a problem with the initialization of the USB audio device or OTG?

[elagil]

It could be anything.. Do you see an unrecognized device in device manager?
Hard to debug without the debugger or panic messages.

[litezxc]

According to my observations, only frequencies with 0% errors can be used with this DAC, as even 0.01% errors result in sound distortion.
According to the table, only 16/96 and 32/48 are suitable for high-quality output on this equipment. I'm going to sleep, see you later!

[litezxc]

dmesg.txt
lusb.txt
usb-devices.txt

[elagil]

Probably I won't have time to debug this until next year. Then I can test with some hardware that I have, which is similar to a blackpill.

[litezxc]

the only issue is with sound transmission, while everything else is already defined and working great ^^

[litezxc]

Happy New Year!

[elagil]

Happy new year! I had some time to test. Please try!
There is a potential bug in the I2S driver of embassy which this works around.

firmware.bin.zip

[litezxc]

It works :)

[litezxc]

The volume control is not working, but sounds great!

[litezxc]

Sometimes there is white noise instead of music, but if you refresh the page, everything is fine.

[elagil]

What do you mean by white noise? Does it sound like a quickly repeating sound?

Please try this one. It should also enable volume control.
firmware.bin.zip

[litezxc]

01033.zip

Sometimes it sounds like this :) Volume control is now working!!!

[elagil]

Cool! That does really sound like white noise. When does it occur?

[litezxc]

It manifests chaotically, it can happen in the middle of a song or right away :) It can be fixed either by restarting the controller or by refreshing the page several times.

[elagil]

Ok, that shouldn't happen of course. I will try to find out why it happens.

[litezxc]

I feel like the solution is somewhere nearby; it might be the buffers

[elagil]

firmware.bin.zip

Please try that, I changed some logic. Might not change anything.

[litezxc]

Right now, there is nothing but noise, and resetting the controller doesn't help, but at least it's stable ;)

[elagil]

Interesting! Not sure why that is yet.

[litezxc]

If we try to double the buffers, we will immediately understand if that's the issue, and we can also check the L2S frequency next time

[litezxc]

Hi, bro! How are you? Do you have any projects in mind that you would like to work on?

[elagil]

Hi there! This one isn't quite fixed yet ;)

[litezxc]

Do you think it’s feasible to use two L2S outputs simultaneously, connecting a separate DAC to each output? This way, we get the following options:

-4 channels
-2 channels single-ended
-And if we invert one channel of each DAC, we can have 2 differential outputs :)

[litezxc]

I just don't know if it's possible to use a common HSE for both outputs and whether there will be perfect synchronization between the channels :)

As for the inversion code, we can try to adapt it from SigmaStudio :)

And one more question regarding the delay when inverting. Theoretically, there shouldn't be any delay since resource consumption is minimal :)

That's the deal, bro :)

[litezxc]

By the way, I was playing around with:

-PeriphClkInitStruct.PLLI2S.PLLI2SN
-PeriphClkInitStruct.PLLI2S.PLLI2SR

in another project and got the same drops and white noise as in our project. Could this be the issue? :)

How to create drops and white noise:

I opened main.c and changed the parameters mentioned above, and voila - noise and drops! :)

[elagil]

Yes, it could be the issue, but it's hard to check the clocks without hardware. I cannot replicate on my setup (I don't have a blackpill).

Do you think it’s feasible to use two L2S outputs simultaneously, connecting a separate DAC to each output? This way, we get the following options:

Why not use the same I2S for multiple DACs? Also, there are differential DACs already, so no need to invert yourself.

[litezxc]

Sad but thrue :)

You can do without DACs at all if you use sigma-delta modulation and PWM output, but you'll have to do a bit of soldering :) like in this example, 32 bits 384 kHz https://github.com/beefdeadbeef/f4uac

By the way, do you have Keil Vision?

[elagil]

Interesting! Doesn't quite reach dynamic range of CD audio, but probably close enough.

No, I don't have Keil.

[litezxc]

Do you know if it's possible to build a project without using Keil Vision? The software no longer supports older versions of compilers, and it's just a mess there? :)

[litezxc]

Here are some sigma-delta projects that work on the 401 and 411 tablets. I tried the one that uses a DAC, but everything works much better without sigma-delta :)

https://github.com/sdima1357/stm32f401cdu6_Audio
https://github.com/sdima1357/stm32f401ccAudioNative

[elagil]

Do you know if it's possible to build a project without using Keil Vision? The software no longer supports older versions of compilers, and it's just a mess there? :)

Sorry, I am not familiar with the Keil ecosystem. You may have to convert a Keil project to something like make/CMake + GCC, in order to build it differently. See for example https://cmake.org/cmake/help/book/mastering-cmake/chapter/Converting%20Existing%20Systems%20To%20CMake.html