ACK in I2C read operation from NRF5340 to NPM1300

[dani_martin]

Hi, we have a NPM1300 chip connected as I2C slave to a nrf5340, acting as I2C master.  Everything works fine, but there is a small detail in the NPM user manual that I would like to confirm:

This is the diagram for a I2C read operation (NPM1300 product specification V1.1 page 122):

So the master sends 4 bytes of data and the slave ACK's all of them. Then the slave answers with one byte and the master ACK's.

But from NRF5340 manual (Product specification v1.5) it clearly mentions that it will NACK the last byte.

So far the communication is working, but I just have question here is: Could you confirm that NPM accepts an NACK as answer?  We just don't want to find failures in this communication because of this.....

Thanks!

[Einar Thorsrud]

Hi,

From what I can see this must be a documentation issu (the nRF5340 behaves the same as the older nRF52 series devices, and the nPM1300 is desigend to work with them, and it works). I am checkign internally go get it confirmed and see how we can improve the documentation.

[dani_martin]

Did you get the opportunity to check this?  Thanks!

[Einar Thorsrud]

Hi,

Yes, I am sorry I forgot to update you. I have confirmed that this is a bug in the nPM1300 documentation. We will update this in the next version of the specification so that it correctly shows a NACK in the end of a read operation.