TPS65982: Start timing of I2C communication

Hi Eric-san,

Thanks, I understood they to read MODE register before reading registers at device start up timing.

Regards,
Takashi Onawa

Hi Eric-san,

Sorry, I got one another question from the customer, regarding I2C access at start up timing

Are the following registers changed before and after the MODE register becomes APP?
The customer want to read the register prior to the polling to minimize waiting time.

Please let me know if there are the register which might be changed.

0x06 CUSTUSE
0x08 Cmd1
0x09 Data1
0x14 IntEventX, IntMaskX, IntClearX
0x15 IntEventX, IntMaskX, IntClearX
0x16 IntEventX, IntMaskX, IntClearX
0x17 IntEventX, IntMaskX, IntClearX
0x18 IntEventX, IntMaskX, IntClearX
0x19 IntEventX, IntMaskX, IntClearX
0x1A Status Register
0x32 TX Source Capabilities Register..
0x34 Active Contract PDO
0x50 Data Control
0x51 DP SID Configuration
0x5F Data Status
0x72 GPIO Status

Regards,
Takashi Onawa

Hi Eric-san,

Also, If you have a diagram for MODE transition, Could you share it with us?
I didn't make sure from our manuals whether the mode accidentally transitions from APP to another or not.

Regards,
Takashi Onawa

Takashi San,

Except for a small subset, the device doesn't allow access to the internal registers and 4CC command while booting - The registers you listed in your above post (except for CMDx and DATAx) are not part of that subset. The host is allowed access to the full register set after the MODE transitions to 'APP'. Chapter-3 of 'www.ti.com/.../slvuah7b.pdf' details the boot flow, but we don't have a document explaining the transitions of MODE register. I'd nevertheless be happy to help if you have any specific questions on the topic.

-/Praneet

Hi Praneet-san,

Thanks for telling the detail.

> The host is allowed access to the full register set after the MODE transitions to 'APP'. Chapter-3 of 'www.ti.com/.../slvuah7b.pdf'

The link seems to be expired. Could you tell me the document name?

Also, My customer would like to know roughly how much time it will take from power up to showing APP on MODE register. Is it possible to estimate the duration roughly?

Regards,
Takashi Onawa

Hi Praneet-san or Anyone in the team,

Can I have any comment for the question above?


Regards,
Takashi Onawa

Takashi San, Please refer the document titled 'TPS65981, TPS65982, and TPS65986 Firmware User’s Guide (Rev. B)' @ 'www.ti.com/.../technicaldocuments'. I never profiled it but can get you the numbers, but this boot time cannot obviously be eliminated - The device has to load the firmware from sFLASH to start working.

-/Praneet

Hi Kumar-san,

Thanks.

We are understanding that the load time can't not eliminate at start up time.

They'd like to define "Timeout" to distinguish Flash read mistake or Flash failure by the sequence below. they think that the information is needed to determine the "Timeout" duration.

Regards,

Takashi Onawa

Hi Kumar-san,

Can I get any comments to close this issue? My customer is demanding us to clarify the time roughly to define the "Timeout" duration in their app's FW.

> Also, My customer would like to know roughly how much time it will take from power up to showing APP
>on MODE register. Is it possible to estimate the duration roughly?

Regards,
Takashi Onawa

Hi Kumar-san,

Thank you for the clear answer. I understood.

Regards,
Takashi Onawa