DS90UB924-Q1: Abnormal low level pulse signal on GPIO8（pin8）when system startup

Cary Wang

Part Number: DS90UB924-Q1

Dears:

We DS90UB947TRGCRQ1 Pair with DS90UB924TRHSRQ1. There is Abnormal low level pulse signal on GPIO8（pin8） of DS90UB924TRHSRQ1, when system startup (SOC is setup DS90UB947 with IIC, not setup DS90UB924 ). Need your great help to analysis. Thank you!

Application and Waveform as below:

over 6 years ago

0 Casey McCrea over 6 years ago

TI__Guru** 103215 points

Hello Cary,

Most likely this is caused by initial locking. Can you also probe the lock pin on 928 during power up to check if it is also toggling?

Best Regards,

Casey

0 Cary Wang over 6 years ago in reply to Casey McCrea

Intellectual 580 points

Dear Casey,

Thanks for your guidance.

Yes it is caused byinitial locking. How to solve the problem? Setup the register of DS90UB947?

0 Jiashow Ho over 6 years ago in reply to Cary Wang

TI__Genius 11340 points

Hi Cary,

Have you tried to probe the lock pin during the 928 power up to see if it's toggling? If the lock pin also toggles, that means once lock is stable the GPIO8 should function as expected.

Best,

Jiashow

0 Cary Wang over 6 years ago in reply to Jiashow Ho

Intellectual 580 points

Dear Jiashow，

Yes, the lock pin also toggles, Signal of GPIO8 and Lock are synchronization.

Would you please analysis what cause the toggles ON Loking PIn and how to avoid the toggles? Thanks!

0 Jiashow Ho over 6 years ago in reply to Cary Wang

TI__Genius 11340 points

Hi Cary,

Does this only happen in system startup? If so, it is most likely due to our AEQ algorithm. At system startup, the AEQ algorithm attempts to sweep the EQ values until it finds a setting that maintains stable lock. During the process, some EQ settings will cause lock drop.

Best,

Jiashow

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DS90UB924-Q1: Abnormal low level pulse signal on GPIO8（pin8）when system startup