Hi everyone,
I’m testing a T5848 microphone with the goal of recording audio (mono) and logging it on an SD card using a nRF54L15DK microcontroller.
However, I’m currently getting no data on the microphone output, and I’m trying to determine why.
Setup :
- Microcontroller: nRF54L15DK
- Microphone: T5848
- uC I/O voltage: 1.8 V (in final design 3.3V with a level shifter)
- Microphone board voltage: 3.3 V (LDO + components)
Tests performed : I have tried to test the microphone without AAD first in both LPM and HQM.
1. I2S clock (SCK, WS) generated by the microcontroller (nrf54l15DK)
-> test in LPM and HQM
2. I2S clock (SCK, WS) generated by an external signal generator (Analogue Discovery 2)
-> test in LPM and HQM
3. Checked datasheets for all components
4. Ensured good grounding on mic board and mic
5. Verified SD pull-down resistor value: 100 kΩ
6. Tested with a 10kΩ SD pull-down resistor
7. Measured current on 1.8 V line:
- Sleep mode: ~2 µA
- HQM mode: ~45 µA
The microphone appears to be correctly powered, but no data is observed on the I2S output.
Problem / Question :
Even though power and current consumption seem normal, I’m still getting no data output from the T5848.
Could the issue be due to the 1.8 V logic level from the microcontroller being too low?
Or could it be related to the I2S timing?
Any suggestions on what to check next (logic thresholds, I2S timing, or configuration)?
I have attach the schematics of the mics