Summary: I2C Issue and Fix
The Problem
The MCP23017 I/O expander (for the keypad) and the ES8311 audio codec both needed to share the same I2C bus (GPIO 18/23) on the LyraT Mini board.
What We Discovered
MCP23017 worked perfectly BEFORE audio_board_init() using the native ESP-IDF I2C driver
After ...

Attaching illustrated pinout for MCP23017
And the keypad

Hello,

I managed to solder the 3 gold pads on my LyraT Mini v1.2 board. With a multi meter I confirmed that the pins are not shorted.

I have a breadboard that is supplied with 3.3V via another IC HW-131. I connected the ground from GND I2C and GND from battery as a common ground in the breadboard ...

According to AI:

❗ SCK is not the same as SCL
Even though the gold pad on your LyraT‑Mini is labeled SCK, it is NOT the I²C clock (SCL).
Instead:
✅ SCK = I²S Bit Clock (BCLK)
Used by the audio codec (ES8311) for digital audio.
❌ SCK ≠ I²C Clock (SCL)
I²C SCL is completely different electrically and ...

Those things are NC in the sense that they aren't connected inside the module, as they're used for PSRAM. I think the Lyra-Mini has test points for the internal I2C bus (labeled SCL/SDA/GND), perhaps you can hook the MCP up to that?


Thank you for your valuable reply. I see that above the audio ...

I have limited knowledge in electronics domain in general so require help here. Most of my research involved asking an AI, so my assumptions could be wrong, in which case, please correct them.

I purchased DIP-28 packaged mcp23017 since I need more buttons for my application. I even purchased a 16 ...