I2S Output Function Lost Even When RAM and Instruction Usage Are Within Range

vader2025 Question

Oct 19, 2025 00:00

Hi Everyone,
I have verified the hardware with a smaller amount of RAM and fewer instructions, and I’m sure the environment is fine — the I2S output works normally in that case. However, after I added another GPIO output control block, the I2S output function stopped working. Although BCLK (3.072 MHz) and LRCLK (48 kHz) are still fine, the data pin remains at a low level. I then tried reducing the audio block instructions by removing the DRC component, and both the I2S output and the GPIO output control worked again.

I’m curious — is there a limit to how much RAM and how many instructions can be used, even if both values are still within the range shown in compiler_output.txt?

The I2S output failed, and the data pin remains at a low level.

After removing the DRC component, both the I2S output and the GPIO output control worked.

Thanks in advance,
Vader

Audio Signal Processors

software

SigmaDSP Audio Processors

adau1701

Report

DaveThib Reply

Oct 20, 2025 00:00

Hello Vader,

This will not have anything to do with memory capacity but with the register settings for the GPIO pins.

The GPIO pins are all multi-function pins so when you set them up for GPIO you remove the other functions. All of the serial port clocks pins and serial input and output pins are on MP pins.

If I were to guess, I am guessing you used the MP6 pin for GPIO which would have removed the SDATA_OUT_0 function for that pin.

Give us the hardware details. Which GPIO pin did you start using?

Thanks,

Dave T

Report

vader2025 Reply

Oct 21, 2025 00:00

Hi Dave,

Thanks for the reply. I’m using two I2S inputs (ADAU1701_RX_I2SD0, ADAU1701_RX_I2SD1, ADAU1701_RX_LRCLK, ADAU1701_RX_BCLK) and mixing the input signal. After that, the signal is split into two I2S outputs (ADAU1701_TX_I2SD0, ADAU1701_TX_I2SD1, ADAU1701_TX_LRCLK, ADAU1701_TX_BCLK). I’ve also added a GPIO control block for PWM output with MP2. Additionally, I’ve confirmed that MP2 is configured as an output GPIO in the hardware settings. It seen the different pin for output control. Is that also affect both audio output and PWM output be lost?

Thanks,
Vader

Report