TPS62869: TPS628692A - I2C read results in a zero

Just FYI, the oscilloscope shots also show the same result during a read transcation. The write is always clean. For example, if i write to register 1 and set the voltage by writing 28h, i see the voltage change. However, the readback always shows zero, like the slave device is unable to respond. 

Hi Vikram,

Thanks for sharing that extra detail.  That shows that the I2C host has the correct address and that the TPS628692A is on and recognizes the I2C commands.

Are you using your own code or the EVM's GUI?

Is the TPS628692A on the same I2C bus as any other device, or is it on a bus by itself?

Can you provide a waveform of the SCL and SDA pins during a read?

Thanks,

Chris

Hi Chris,

We are using our own code to read the values. 

Here's the waveform (cropped to fit the text box) while reading back TPS628692A

Reading back any other IC works fine. 

Thanks for sending.

Did you try reading register 2 or 3 or 5?  What I2C speed are you running?

Would you be able to check if this GUI reads successfully? https://dev.ti.com/gallery/view/TPSM8286xC/TPSM8286xCEVM_GUI/ver/1.0.0/ You can choose the CA3 IC version, at the popup box.

Do you have an EVM that you could try your code on?

Thanks,

Chris

Hi Chris,

I did try register 2, 3 and 5 and its the same thing, reads back zero but i was able to verify the write was successful. I'll try theTI GUI and get back to you.

I don't think we have the EVM at this point, but let me check.

Thanks for trying.  Let me know if the GUI works.

Also, if you want a free EVM or samples (to test a different IC, etc.) for debugging this, send me an address in a private 'conversation' and I can request those for you.

Chris