TPS65987D: Using default configuration to boot Linux system from USB stick

Velykokhatko Sergey

Part Number: TPS65987D

Hi all,

We have the following use case: ApolloLake SOC and TPS65987D for using in DRD mode. The USB-HS signals routed directly to ApolloLake from USB-C

Our idea is to start Linux from USB stick in production case. I mean in case, when the board contains not programmed SPI-NOR for TPS65987D. Is it possible? If yes, then some other questions to it

As I see the TPS65987D has the default configuration 2

for probably our case

And as I understand we can select the configuration 2 via combination of resistors on ADCIN1 but what should we do with the SPI_MISO? We have now the pullUp on this pin as it is defined i datasheet.

For Usb_Vbus_Detect we wanna use the GPIO14 event and for Usb_OTG_ID the GPIO13 event. Should we implement any pullUps/pullDowns to get the feature for our case running? Will that pullUps/pullDowns not disturb the functionality of TPS65987D when the SPI-NOR not yet flashed and in case when it is already flashed?

Thanks,

Best Regards,

Sergey

over 5 years ago

0 Prajith Cheerakkoda over 5 years ago

TI__Expert 8680 points

Hi,

I'm looking into your query. Could you upload images again? I'm not able to see them.

0 Velykokhatko Sergey over 5 years ago in reply to Prajith Cheerakkoda

Prodigy 235 points

Hi,

I tried to upload the screenshots from datasheet. Probably they are not needed. That was the screenshots from part of Table 5 and from Table 7 from datasheet

Thx,

Sergey

0 Prajith Cheerakkoda over 5 years ago in reply to Velykokhatko Sergey

TI__Expert 8680 points

Hi Sergey,

You want the end product (Apollo SOC and TPS65987D) to be able to boot from external USB2 stick when on board SPI flash is not programmed. Is my understanding correct?

Default configurations will not work with the SPI MISO pin pulled high.

Thanks

Prajith

0 Velykokhatko Sergey over 5 years ago in reply to Prajith Cheerakkoda

Prodigy 235 points

Hi Prajith,

>You want the end product (Apollo SOC and TPS65987D) to be able to boot from external USB2 stick when on board SPI flash is not programmed. Is my understanding correct?

Yes.

>Default configurations will not work with the SPI MISO pin pulled high.

Will it work, when we make PullDown?

Thx a lot,

Sergey

0 Prajith Cheerakkoda over 5 years ago in reply to Velykokhatko Sergey

TI__Expert 8680 points

Hi Sergey,

Yes, it will work. But Configuration-1 is what you need to use for this.

Note: Config 1 will work only when I2C address is 0x20. Please set ADCIN2 accordingly.

If this answers your question, PLEASE select This resolved my issue

Thanks

Prajith

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TPS65987D: Using default configuration to boot Linux system from USB stick