EC25 and NAU8810 two wire communication

Hi Guys

We have created a system including an EC25 modem and NAU8810 codec.

All works well, however we have a system issue that arrises after we make a voice phone call.

The phone call works well but configuration of the NAU8810 during (or before) the call causes our system issue. On a scope we can see that the EC25 has two interactions with the NAU8810. One write after power up and one write for a phone call. Im guessing they are writes.

We need to control the NAU8810. Right now we think we need to reverse the write that the EC25 does before the call. We can do this but we would like confirmation about what specifically the writes are.

Where would we get this confirmation? Is it documented somewhere?

Thanks for any help in advance


Please check the
maybe it will help you.


Thanks for the documentation

I already fixed this with a scope and the NAU8810 data sheet.

The setting of register 0x01 needs to be controlled in our application. This is now implemented in our latest SW

But i will review the documentation and will learn more, no doubt.

Thanks again


Hi Guys

Thanks for the docs, they make for interesting reading.

We have moved on now and have discovered another annoying quirk in the system.

Occasionally the system comes up, after a power cycle, with no audio during a phone call. Investigating we found that the NAU8810 register settings are not correct (or at least not the same as when we have audio in a call).

So the configuration of the NAU8810 has not happened completely. Many of the first set of registers 0x00 to 0x0A are all 0x00 while some later registers have the correct value.

I am wondering when this configuration of the NAU8810 occurs. Is it when we set the preferred CODEC option with the AT command?

Im assuming that all the register configuration happens over the I2C lines. Is it possible that the EC25 is up and configuring the NAU8810 before the NAU8810 is ready? Would it fix the issue if we delayed the selection of the Codec?

Thanks for your help.


Is the EC25 a standard product or QuecOpen? If it is Open, please post question in the Open area. If it is a standard part, as you mentioned, this is a bug or a problem, and it cannot be solved on the forum, please submit a ticket.
I am sorry.


Thanks again for your assistance

Where should I submit a ticket?



Hi @dgleeson

Could you write the fw verison you are using. And btw I’d like to ask why you want to configure the codec reisters, for us, the codec has been adapted by Quectel, you can use it directly if no any issues from HW side I mean. So could you provided the details and let us better understanding. Thanks.