Not code issue but issue with wiki for HiLetgo PCM5102 I2S IIS Lossless Digital Audio DAC Decoder

[Oasis-Enterprise]

Problem Description

Wish there was a better way to comment this as it is not an issue with your code but wanted to give a quick heads up. On your DAC wiki's for the HiLetgo PCM5102 I2S IIS Lossless Digital Audio DAC Decoder. There are a ton of copies of this module on amazon that are not HiLetgo. I have been struggling to get them working and just learned that on those the sck needs to go to 5v not gnd per your wiki. Understood your wiki is for HiLetgo PCM5102 I2S IIS Lossless Digital Audio DAC Decoder and that it is probably correct for that just thought I would give my experience with off brand as I have been banging my head trying to get it to work figured others were too.

Device Description

PCM5102 I2S IIS Lossless Digital Audio DAC Decoder with ESP32

Sketch

See above not code related but was not sure where to add the comment in repo besides here.

Other Steps to Reproduce

No response

Provide your Version of the EP32 Arduino Core (or the IDF Version)

2.3.4

I have checked existing issues, discussions and online documentation

• I confirm I have checked existing issues, discussions and online documentation

[pschatzmann]

I am afraid this does not make any sense. Here is the info from the Technical Sheet:

System Clock PLL Mode

The system clock PLL mode allows designers to use a simple 3-wire I2S audio source when driving the DAC.
The 3-wire source reduces the need for a high frequency SCK, making PCB layout easier, and reduces high
frequency electromagnetic interference.
The device starts up expecting an external SCK input, but if BCK and LRCK start correctly while SCK remains at
ground level for 16 successive LRCK periods, then the internal PLL starts, automatically generating an internal
SCK from the BCK reference. The PCM510x disables the internal PLL when an external SCK is supplied;
specific BCK rates are required to generate an appropriate master clock.

So as a conclusion you either connect the master clock pin from the ESP32 or you have leave it low.

Did you double check the solder bridges against the recommended values ?

[Oasis-Enterprise]

Ya the I had the soldered bridges as you had mentioned in wiki to check if no audio. On soldered bridges I have 1,2 and 4 low and 3 high. Here is the board I am using for it. https://www.amazon.com/dp/B09C5QX228?ref=ppx_yo2ov_dt_b_fed_asin_title. I am with you that every piece of documentation I found told me to pull sck to ground but when i finally resorted to chatgpt for some help it told me to connect sck to vcc pin on esp32 and once I did that everything worked perfect. My gut tells me that the off brand boards maybe have something a little off from the HiLetgo boards? Not trying to say you are wrong hope it is not coming across like that just wanted to add my findings in case they help someone.

[pschatzmann]

Strange: I am still trying to figure out why this would be. The only other option that I found, is that it might be possible to leave it unconnected.

What happens if I connect HiLetgo PCM5102 BCK pin to high

ChatGPT said:
If you connect the BCK (Bit Clock) pin of the HiLetgo PCM5102 DAC module directly to high (e.g., 3.3V or 5V), the DAC will not function correctly and may even behave unpredictably or get damaged over time. Here's what happens in detail:

1. BCK is an input for a clock signal
   The BCK pin expects a clock signal that indicates the timing for each bit of audio data.

It's a digital input, not a logic-level control pin.

Driving it high constantly means there's no real clock signal, just a constant voltage.

2. Possible outcomes of tying BCK high
   No audio output: The PCM5102 won't know when to read data, so it won't output audio properly.

Internal logic may hang: The chip may stall internally if BCK doesn't toggle.

Potential heat/damage over time: If internal circuits try to sync to a nonexistent or constant clock, it might stress the chip.

3. Correct usage
   BCK should be driven by a digital audio source (like I2S from a microcontroller or SBC like Raspberry Pi or ESP32).

It should be a square wave in the MHz range depending on the audio sample rate and bit depth.

Summary
Do not tie the BCK pin high. It must be driven with a proper I2S bit clock signal. If you're not using I2S yet, leave it unconnected or pulled down gently until your audio controller (e.g., ESP32) starts transmitting.

Would you like help wiring the PCM5102 to an ESP32 or Raspberry Pi?

[Oasis-Enterprise]

I see you asked about the BCK, i was speaking about the SCK not BCK. Here is the conversation transcript I had with Claude not ChatGPT (thought it was chatgpt) "Ah, I see the issue now. Your wiring description helps a lot. There's a problem with how the PCM5102A DAC is connected. Let me correct this:
The SCK pin on the PCM5102A should NOT be connected to ground. This pin is for the System Clock configuration. Here's the correct wiring for the PCM5102A:

Power connections:

VCC on PCM5102A → 5V (from your buck converter)
GND on PCM5102A → GND (common ground from your power supply)

I2S connections:

DIN on PCM5102A → GPIO 22 on ESP32 (data)
BCK on PCM5102A → GPIO 26 on ESP32 (bit clock)
LCK/WS on PCM5102A → GPIO 25 on ESP32 (word select/left-right clock)

Configuration pins on PCM5102A:

SCK should be connected to VCC (5V), not ground. Connecting it to ground could be causing your issues.
XMT should be connected to GND (to enable the DAC)
FMT should be connected to GND (for I2S format)
FLT should be connected to GND (filter setting)
DMP can be left unconnected or connected to VCC

The SCK pin is particularly important - it configures the system clock source. When connected to VCC, it sets the DAC to use the BCK/LCK pins for clock timing, which is what we want for I2S mode.
Try making this correction (connecting SCK to 5V instead of ground) and then run this simplified test code:"

[pschatzmann]

I have updated the documentation. Did you try to leave it unconnected ?

[Oasis-Enterprise]

Yes I did try unconnected that provided no sound, the only way I have been able to get these off brand amazon ones to work is connecting sck to 5v on esp32.

[BluCobalt]

Using https://a.co/d/bUUvg4a, with the bridges and pins connected as described in the wiki, I have working audio. Granted, it's only on the left channel, (so I assume there's some issue I haven't figured out yet) but it works.

[joba-1]

from the amazon picture it looks like the sck-gnd solder bridge is preconnected with a small resistor because most people need that anyways.

If you need to use an external clock with these modules the best would be to remove that bridge and not to provide 5V and have a permanent unknown but potentially high current

[Oasis-Enterprise]

I got the 3 pack, I am going to mess with one of them tonight and try and remove that and see what that does, good call out.