TPS65721: I2C continuous reading error

Hi Alexey,

Are any faults or interrupts being tripped? Are you writing anything to any of the registers in between reads?

Best,

Emily

Hi Emily,

Emily Kong1 said:

Are any faults or interrupts being tripped?

No. I adjusted my app to exclude any other operations with I2C bus before this continuous reading - with the same result. No any writing before...

Alexey,

Is the PMIC and all regulators operating as expected? As in, this issue extends only to I2C reading all registers simultaneously?

Best,

Emily

Emily Kong1 said:

Is the PMIC and all regulators operating as expected? As in, this issue extends only to I2C reading all registers simultaneously?

Yes, PMIC works as expected: SYS voltage is 5V, DCDC1 = 3,3V, LDO1 = 3.3V (HOLDed, non-breackable). LiPol rechargable battery 3,7V connected to BATT, USB power - to AC.

The problem appears only when I try to read more of 1 reg in the same time in the one I2C request.

Alexey,

Can you verify that you have the latest software support files downloaded? If yes, I would recommend probing SDA and SCL when reading all registers simultaneously vs. one by one to see if you can isolate the issue with I2C. 

Best,
Emily

Hi Emily,

This SW pack isn't applicable in our case because we don't use TPS65720_1EVM developer board.

Anyway, on the screenshots from my topic-start post you can see the signals directly from the PMIC pins - SDA, SCL, & INT, before any modification by SW application.  

BR,
Alexey

Hi Emily,

I have additional information: continuous writing works incorrectly too. Please see at screenshots.

The test conditions is very simple: I want to setup my own bitmap to IRQ mask registers TPS_IRMASK0-:-TPS_IRMASK2. I want to allow all possible interrupts but, according datasheet, we must keep bit B4 in TPS_IRMASK0 and bit B0 in TPS_IRMASK2 as unchanged. It means that I should write 3 bytes 0x10, 0x00, 0x01 from start reg TPS_IRMASK0 (reg addr is 0x0D).

As you can see on the 1st screenshot, the continuous writing finished without any error; it looks like everything is OK. But immediately after write data I check the content on these registers. At the 1-st reg  TPS_IRMASK0 I see correct information 0x10, but the rest registers TPS_IRMASK1 & TPS_IRMASK2 still have default data 0xFF. It means that previous writing operation was not finished successfully.

  begin of sequence

end of sequence (sorry for different scale).

Quick update: There is the result of one-by-one writing process to the same registers. Everything is really OK.

BR,
Alexey

Hi Kevin,

Thank you so much for clarification! The latest datasheet for this PMIC has the release (revise) date MAY 2018. I was hoping that such important information about I2C release level would be mentioned on the 'Revision history'/'Errata' chapters...

Anyway, Thank you again!

BR,

Alexey