tps65982 pp_ext wait for SRDY quetsion

kevin wu

In 65982d, I set 0x28 bit30~28 to be 011 in firmware, it mean the power cannot enter system without SRDY command via PP_EXT.

When 982d power on from dead battery mode, the power can enter to system via PP_EXT.

However, there is no way to turn off besides disable pp_ext in 0x28.

But in 982 v1.11.05 firmware and same condition, i can turn off the power path by SRYR.

Can i know which behavior is correct and my customer ask this function in some use case.

BTW, in 0x1a, 982d show pp_ext is disable and 982 show it is sink power from above case.

over 8 years ago

0 Rahul Sharma16 over 8 years ago

TI__Expert 6430 points

Hi Kevin,

The right way is to use SRYR command to turn off the active switch. SRYR is a non sticky one time command and will disable the switch when called, but in event of renegotiation or disconnect-connect sequence the port will go to the default status.

After using SRYR, you need to use SRDY command to enable the switch again.

Hope it answers.

Thanks,

Rahul

0 kevin wu over 8 years ago in reply to Rahul Sharma16

TI__Intellectual 2670 points

so 982 have the correct behavior, but not for 982d right?

because i can do it in 982 but not in 982d when dead battery

Or you have other method to do this?

0 Rahul Sharma16 over 8 years ago in reply to kevin wu

TI__Expert 6430 points

Hi Kevin,

982D should behave exactly the same and should follow the same procedure as 982.

Thanks,
Rahul

0 kevin wu over 8 years ago in reply to Rahul Sharma16

TI__Intellectual 2670 points

When 982d power on from dead battery mode, the power can enter to system via PP_EXT.

However, there is no way to turn off besides disable pp_ext in 0x28.

But in 982 v1.11.05 firmware and same condition, i can turn off the power path by SRYR command.

So is it a issue in 982d firmware?

0 kevin wu over 8 years ago in reply to kevin wu

TI__Intellectual 2670 points

i found 982d do not update the power path status to status register in this use case, and after i update it, and the function works.

But i still think it should fix by firmware.

BTW, the issue still happened in v2.6 and v2.2. firmware.

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tps65982 pp_ext wait for SRDY quetsion