INA226: Multiple reads on same register after one write.

Nick Hileu

Part Number: INA226

I am having some issue with reading same register value of INA226 after one write.

In particular, I am trying to read VBUS , after one write register pointer of 02H, the first read is successful, of course.

The appending reads seems fail until I write register pointer value 02H again.

By the way, it seems there is a "timeout" between write register, and read register. Say if I write register 02H, and wait , say 20 milli seconds, and do a read, the result is not as expected.

IIC is running at standard speed.

Any ideas?

Cheers,

Nick

over 2 years ago

0 Mitch M over 2 years ago

TI__Genius 17990 points

Hey Nick,

Thanks for using the TI forum.

That does seem odd. Can you send a scope shot of a failing communication so that I can help verify that the timing requirements are met?

0 Nick Hileu over 2 years ago

Prodigy 10 points

Hi Mitch,

Thanks for the quick response. It is not INA226's fault after all, I looked through code, the following behaviour is what I saw:

Doing multiple reads after one write works fine.

However, reads takes some time in a compact loop and cause the other part of program have a very small lag.

Maybe the lag was caused by my overhead (STM32 HAL layer), or caused by INA226, I am not sure, I will investigate more and see.

0 Mitch M over 2 years ago in reply to Nick Hileu

TI__Genius 17990 points

Hey Nick,

Ok, good to know. Thanks for updating the thread.

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INA226: Multiple reads on same register after one write.