INMP441 Mic AudioInI2S library co-working with this HUB75 library

[cblx5]

Hi,

I am building an audio spectrum analyser using the above two libraries. The AudioInI2S outputs a simple list of freq bins and strengths which I was planning to display on a 32x128 LED matrix using a plain ESP32. Both libraries work independently. But will not work together as I get spurious data. I am (nearly) sure its because both libraries use DMA channel 0. Can someone please advise if I can get around this? Have I missed something. Co-pilot thinks the HUB75 library may be switched to channel 1, but then 'changed' its mind. Also if I switch to an ESP32 S3 will the above work because of GDMA? Please assume I am just a hobbyist. Thanks

[cblx5]

"mrcodetastic
on Nov 5, 2021
Maintainer
Yes. Just do a search replace in ESP32-HUB75-MatrixPanel-I2S-DMA.cpp for I2S_NUM_0 and change it to I2S_NUM_1

There are two lines."

I found above despite all previous searches ....... I will try this shortly

[board707]

I am (nearly) sure its because both libraries use DMA channel 0.

Why don't you think the reason is that both libraries use the i2s interface?
This is just a guess, but it seems more likely to me than problems with the DMA.

[cblx5]

Hi,

My understanding is that there are 2 DMA channels on plain ESP32 - channels 0 and 1. Both above libraries use I2S and default to DMA channel 0, so my 'glued' together code is reading microphone samples from DMA channel 0 and writing LED data to channel 0 which is a conflict. I need to read mic data from channel 0 and write LED data to channel 1. Please let me try post no.2 first.

I am assuming I2S_NUM_0 uses DMA channel 0 and I2S_NUM_1 uses DMA channel 1, which may be wrong?

Thanks

[cblx5]

Hi,

Apart from the references below - I can see no reference to I2S_NUM_1, please help to explain how to move to I2S_NUM_1 or DMA Channel 1?? Is there some function I need to call to specify channel 1?

if (ESP32_I2S_DEVICE == I2S_NUM_0)

and

i2s_dev_t* getDev()
	{
	  #if defined (CONFIG_IDF_TARGET_ESP32S2)
		  return &I2S0;
	  #else
		  return (ESP32_I2S_DEVICE == 0) ? &I2S0 : &I2S1;
	  #endif

	}

[mrcodetastic]

I would use an ESP32 S3. It's a much newer chip and the HUB75 output uses a totally different peripheral that is the LCD module.

[cblx5]

OK thank you, by co-incidence I was going to try the S3 ......thinking GDMA..... and its arriving Mon/Tues. I will look forward trying LCD code. Thanks

[cblx5]

 #elif defined (CONFIG_IDF_TARGET_ESP32S3)
  
  //#pragma message "Compiling for ESP32-S3"
  #include "esp32s3/gdma_lcd_parallel16.hpp"
  #include "esp32s3/esp32s3-default-pins.hpp" 

......still learning :-))

[cblx5]

Thank you, mrcode-fan-tastic !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Audio spectrum analyser working, but my graphics are rough, rough, rough and slow (delay()s, white bars not doing a peak hold) :-))))))). Just removed ESP32, added more header (socket)pins to accommodate 6 extra pins for S3, and rewired for DEFAULT ESP32 S3 pin recommendations and it all burst into life ( compiler actually reported it was using the "pragma.... LCD......" mode). I can see the audio strength data by frequency bin that I am expecting but as above my graphics are rough and slow at the moment.

Audio_Analyser.mp4

LEDS are more vibrant than video.