DS90UB947-Q1: Ccommunication between ds90ub947 and DS90UB948

Qianqian

Part Number: DS90UB947-Q1

Hello TI Experts,

I am now using DS90UB948, cooperate with car factoty who mainly focus on host and DS90UB949~

I'd like to ask you a question：

If the screen is not bright successful, how to determine whether it's 949 's written into I2C error or 948's received error?

over 5 years ago

0 Steven(Shenzhen) Shi over 5 years ago

TI__Mastermind 30515 points

1. you can check the UB949 hdmi status reg., and UB948's receiver status (lock? CRC error?)
2. you can run the pattern gen. for this test
3. you can read / write reg. to check the I2C link availability?

regards,
Steven

0 Qianqian over 5 years ago in reply to Steven(Shenzhen) Shi

Genius 5010 points

Hollo Steven,
Thank you for your reply~

During the whole system test,the screen is black by accident,is their any way to know whether the problem is caused by 949 or 948 quickly?
My customer is focused on 948, 948 is passive device, Can 948 I2C feedback the lock states?

0 Steven(Shenzhen) Shi over 5 years ago in reply to Qianqian

TI__Mastermind 30515 points

Yes, you can check 0x1c referring to ub948 d/s.

regards,
Steven

0 Qianqian over 5 years ago in reply to Steven(Shenzhen) Shi

Genius 5010 points

Hello Steve,

Thank you very much for your help~

Now we met with a new problem:

When their is a key trigger,MCU will send INT to 948,and send data to 948 by I2C,

The blue line means INT,yellow means SCL, red means data,why it drops to 1V rather than 0V?

pullup regsister is 4.7K, I2C voltage is 3.3V

0 Steven(Shenzhen) Shi over 5 years ago in reply to Qianqian

TI__Mastermind 30515 points

I don't know ether :(.
but you can inspect the external circuit design on INTB and I2C, are they designed correctly? From the waveform, it seems the SCL swing is also not correct. the supply voltage is correct?...you need be patient to identify the I2C link firstly. it should not matter with INTB signal.

regards,
Steven

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DS90UB947-Q1: Ccommunication between ds90ub947 and DS90UB948