DS90UB948-Q1: How to detect external lvds signal in test pattern mode using internal clock？

user1373865

Part Number: DS90UB948-Q1

Hi all,

I'd like to enter test pattern mode using internal clock when the lvds signal is lost, and exit test pattern mode when the lvds signal is connected again.

Now I detected the lock pin becoming low to enter the test mode, but can't exit it because the lock pin always is high.

How to detect external lvds signal in test pattern mode using internal clock？

Thanks very much!

Reliya

over 7 years ago

0 Wu JW over 7 years ago

TI__Intellectual 2935 points

Hi, user1373865,

You need try other way to exit the test mode.

Can you have other way to detect the external LVDS signal? Such as the power signal for system or some external line detection circuit for the LVDS signal.

0 user1373865 over 7 years ago in reply to Wu JW

Prodigy 50 points

Thanks for your reply！

I tried to access the register of DS90UB947, it is failed when in test pattern mode.

It means we can't access the remote DS90UB947 in test pattern mode, is it right?

0 Steven(Shenzhen) Shi over 7 years ago in reply to user1373865

TI__Mastermind 30515 points

Hi,
UB947's register can be visited in test pattern.
to exit test pattern mode, you can check the PLL status referred to OLDI PLL. please give me one mail, our FAE can contact with you. thanks.

best rgds,
Steven

0 user4696388 over 7 years ago in reply to Steven(Shenzhen) Shi

Prodigy 50 points

Hi Steven,
This is my customer, you can give me a email, and I will loop in customer and TI, thank you very much~
My email address is hubery.he@arrowsisa.com.

0 user1373865 over 7 years ago in reply to Steven(Shenzhen) Shi

Prodigy 50 points

Hi Steven,

My email is kejunshi@sysom.com.cn. You can also send to hubery.he@arrowsisa.com together.

Thanks!

0 Steven(Shenzhen) Shi over 7 years ago in reply to user1373865

TI__Mastermind 30515 points

Hi Hubery, you can contact with our FAE for setting. thanks.

best regards,
Steven

0 Wu JW over 7 years ago in reply to Steven(Shenzhen) Shi

TI__Intellectual 2935 points

Hi, Steven,

Customer question is followed. How to exit the DS90UB948 from pattern mode when the LVDS signal reconnected?

When LVDS disconnect, in UB948 side, it will detect the LOCK pin signal to set the UB948 to pattern mode, customer want to use this function to get the blue screen at the display side.

When 948 enter the pattern mode, the internal clock signal will let the LOCK pin as high, the mcu can't know when the LVDS signal is reconnected. So can't let the 948 to exit the pattern mode.

Do you any suggestion to how to realize the function?

0 Steven(Shenzhen) Shi over 7 years ago in reply to Wu JW

TI__Mastermind 30515 points

JW,

there are some options to implement your function through the total system design. for examples:

1. You can send one speical GPI signal from UB947, when connected every time, once the corresponding GPO in UB948 can detect this signal, it means the link is built up.

2. You can check the EQ status and link status inside UB948 (0x1c, 0x44), or can try to visit UB947 registers from the UB948's on-board I2C master to detect whether the UB947 is alive.

best regards,

Steven

0 user1373865 over 7 years ago in reply to Steven(Shenzhen) Shi

Prodigy 50 points

Hi Steven,

I tried your idea.
>> 1. You can send one speical GPI signal from UB947, when connected every time, once the corresponding GPO in UB948 can detect this signal, it means the link is built up.
In normal case, the GPO2 is high. But if the lvds is disconnected, the GPO2 always is low.

>>2. You can check the EQ status and link status inside UB948 (0x1c, 0x44),
The register of UB948 (0x1c, 0x44) does not change in test pattern mode.

>>or can try to visit UB947 registers from the UB948's on-board I2C master to detect whether the UB947 is alive.
In test pattern mode, can't access UB947's register from UB948.

Do you have any other idea?

Thanks.

Reliya

0 user1373865 over 7 years ago in reply to Wu JW

Prodigy 50 points

Do you have any solution？
Thank you.

0 Wu JW over 7 years ago in reply to user1373865

TI__Intellectual 2935 points

Hi,

I had sent a email to you in before. I will re-send it. Pls check.

0 Steven(Shenzhen) Shi over 7 years ago in reply to user1373865

TI__Mastermind 30515 points

You can try to check the link error and the link status register in the UB948 side. also, you can generate the blue screen from the video control IC once cable is lost? thanks.

best regards,
Steven

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DS90UB948-Q1: How to detect external lvds signal in test pattern mode using internal clock？