Watch dog about DM8168

Lei Wong

Expert 1355 points

Hi everyone,

We made a board using DM8168 chip, and when we test the board, it cannot boot up.

I found the WD_OUT pin is always high on my board.

In this post thread,

http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/717/p/106595/375825.aspx#375825

It said a board modification is needed, and this is the details

http://processors.wiki.ti.com/index.php/DM81xx_AM38xx_PSP_WDT_Support#Board_Modification

A 10K pull down resistance is needed.

I don't know if this is the reason about my boot up problem.

The DM8168EVM works OK, and I didn't find the 10K pulled down resistance on the EVM board,

if there is a problem as the post thread said, then why EVM can boot up?

Regards,

Lei

over 13 years ago

0 Parth Saxena over 13 years ago

TI__Intellectual 1265 points

Lei,

If the board modification is not done, then also the board should boot-up (that is why the EVM also boots up). The board modification that is mentioned in our document is needed when the system has to reboot due to WDT timeout. If the modification is not done, the system won't be able to reboot if the WDT times out. So, I don't suspect this to be the reason for your boot-up problem (assuming that your board does not even boot up initially).

Regards,

Parth

0 Lei Wong over 13 years ago in reply to Parth Saxena

Expert 1355 points

Hi Parth,

Yes, it seems that the DDR is not working. I think maybe this is the reason that the board (u-boot) cannot boot up.

Regards,

lei

0 Parth Saxena over 13 years ago in reply to Lei Wong

TI__Intellectual 1265 points

Lei,

I recommend you to close this thread by verifying the previous answer and start a new thread expressing the DDR issue.

Thanks and Regards,

Parth

0 Lei Wong over 13 years ago in reply to Parth Saxena

Expert 1355 points

OK, Thanks Parth.

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Watch dog about DM8168