ADAU1701: MP5 goes high when I set it as input

Hello Peter,

The input pins if they are floating and not attached to anything will float up high. When they are set as an input they float up high for the same reasons if there is nothing driving them. This is normal.

Now when you say you set it to Input Bclk_In and it blocks the bit clock source? This is concerning. Do you have a schematic of what is actually attached to the pin?

Dave T

Hello Dave!

As first attempt, I tried to drive the I2S input of ADAU1701 module with my previous project based on an Atheros AR9331 SoC (Carambola2 SoM), a TI ISO7240 digital isolator and an ES9028 DAC chip - I tried to connect the ADAU module parallel to I2S output of the CPU before the digital isolator. Connection of DATA and LRCLK does not bother the I2S stream, the ES DAC chip works well, but when I connect the BCLK too, it pulls up the output of the source and it disables the ES DAC too...

The 308th page of AR9331 datasheet says: driving capability of GPIO pins up to 24mA, so I think it should be more than enough to drive both the isolator and ADAU chip...

https://www.openhacks.com/uploadsproductos/ar9331_datasheet.pdf

Do I have to try to connect the module through something that act as an output buffer, like a 74HC245?

Peter

Hello Peter,

What pin number are you connecting to for the bit clock? I do not understand your pin naming in your diagram.

The pin is either the wrong pin or it is not set properly in the registers. Please attach your project as well.

It is looking like the pin is either an output or set to be an output.

Thanks,

Dave T