Search found 15 matches

by danak6jq
Mon Sep 23, 2019 4:57 pm
Forum: Hardware
Topic: ESP32 LyraT v4.3 Aux input circuit is highly confusing and surely wrong
Replies: 17
Views: 4101

C66 has to be wrong, too (was Re: ESP32 LyraT v4.3 Aux input circuit is highly confusing and surely wrong)

C66 is effectively from a DC bias slightly lower than Au_VCC33, coupled to ground via 10uF. It looks completely wrong for capturing audio.

Cheers,
Dana K6JQ
by danak6jq
Mon Sep 23, 2019 1:57 pm
Forum: Hardware
Topic: ESP32 LyraT v4.3 Aux input circuit is highly confusing and surely wrong
Replies: 17
Views: 4101

Re: ESP32 LyraT v4.3 Aux input circuit is highly confusing and surely wrong

Thank you for looking into this. I also do not understand the purpose of C66 and expect it would also reduce the audio quality of the right input. I understand that R78 / R132 is for Aux Detect (detect when a connector is plugged-in to the jack), R107 is intended to load the right input the same as ...
by danak6jq
Mon Sep 23, 2019 12:23 am
Forum: Hardware
Topic: ESP32 LyraT v4.3 Aux input circuit is highly confusing and surely wrong
Replies: 17
Views: 4101

ESP32 LyraT v4.3 Aux input circuit is highly confusing and surely wrong

The Aux input from the 3.5mm Aux input jack has a 0.1 uF capacitor from left channel to right channel (C62), as well as 0.1u caps shunting each of the left and right inputs to Au_ground (C64, C65). This seems really wrong for audio input processing. Anyone have any idea why? I'm about to look at the...
by danak6jq
Mon Sep 23, 2019 12:18 am
Forum: ESP-IDF
Topic: How to configure LyraT v. 4.3 board to sample audio data from AUX input?
Replies: 4
Views: 1393

Re: How to configure LyraT v. 4.3 board to sample audio data from AUX input?

If I understand correctly, you're using the esp-idf example i2s_adc_dac, which uses the internal ADC and DAC and does nothing to interface with the ES8388 codec on the LyraT 4.3 board. What you need to do is configure the ES8388 codec via i2c, configure i2s 0 for the desired sample rate, and then us...
by danak6jq
Sat Nov 24, 2018 7:03 am
Forum: General Discussion
Topic: Use ESP32 as MCU (no radio) -- Certification needed?
Replies: 1
Views: 956

Re: Use ESP32 as MCU (no radio) -- Certification needed?

I am not an attorney, but, if you don't turn the radio on and don't attach an antenna to the chip, then it's not an intentional radiator. So I'd think it's like any other MCU in that case - you may still require some FCC certification for Part 15.

Cheers,
Dana

Go to advanced search