DS90UB927Q-Q1: configuration to work with 928

Gene Qiu

Part Number: DS90UB927Q-Q1

Hi Team,

At present, ds90ub927 is used as serializer and 928 as de-serializer. Link is MCU - > 927 - > 928 - > touch screen

I accessed 927 on the MCU side. The I2C address is 0x0c. It is possible to read the value of 0x00 registers as 0x18, which is correct.

928 I2C address 0x34, access this 0x34 directly with mcu, read the value of 0x00 register is wrong.

Touch screen address is 0x38, access this 0x38 directly with mcu, read the register inside is also wrong.

How do I configure 927 to access 928 and the touch screen behind 928?

Best Regards,

Gene

over 5 years ago

0 Charley Cai over 5 years ago

TI__Genius 12866 points

Are the 927 and 928 locked?
If you read 927 register 0x06, do you get back anything?

Best Regards,
Charley Cai

0 Gene Qiu over 5 years ago in reply to Charley Cai

TI__Intellectual 1720 points

Hi Charley,

The main board of panoramic project uses GPIO0 of DS90UB927 and DS90UB928 of LCD as backlight PWM control, GPIO1 as TP_INT touch interrupt. At present, image display OK, reverse GPIO1 touch interrupt OK, and configuration GPIO0 from 927 to 928 is unsuccessful. The phenomenon is that GPIO0 of 927 is square wave of PWM, 928 is low level, please help solve it. Thank you!

Already set the GPIO as per datasheet like below.

0 Charley Cai over 5 years ago in reply to Gene Qiu

TI__Genius 12866 points

What is the frequency of the PWM?
If I understand correctly, you got a PWM signal at 927 GPIO input, but it is not propagating through?

Just to make sure, the GPIO's on 927 are configured as input, and GPIOs on 928 are configured as output right?

Best Regards,
Charley Cai?

0 Gene Qiu over 5 years ago in reply to Charley Cai

TI__Intellectual 1720 points

Hi Charley,

1. the PWM is 50kHz, 3.3 V amplitude;
2. 927 configured as input, and 928 as output;
3. I2C works fine, image display OK, touch interrupt OK,
just PWM signal at 927 GPIO input, can not propagate through to 928, and 928 is low level

Apprecaite for your help!

Gene

0 Gene Qiu over 5 years ago in reply to Charley Cai

TI__Intellectual 1720 points

Meanwhile, do we have any demo code which shows how the PWM propogate through 927 and 928? If so, could you send me via Email
gene-qiu@ti.com

0 Charley Cai over 5 years ago in reply to Gene Qiu

TI__Genius 12866 points

Can you send a DC GPIO signal from 927 to 928?

Meanwhile, i will look into whether we have some demo code.

Best Regards,
Charley Cai

0 Gene Qiu over 5 years ago in reply to Charley Cai

TI__Intellectual 1720 points

Hi Charley

Yes, set high, 928 would be high. Low, 928 would be low. But can not PWM
Could you please send me via Email? Since I can not find your name on infolink?

Gene

0 Gene Qiu over 5 years ago in reply to Charley Cai

TI__Intellectual 1720 points

Hi Charley,

How is the progress now? Is there any demo code you can send to me via gene-qiu@ti.com
Much appreciated!

Gene

0 Charley Cai over 5 years ago in reply to Gene Qiu

TI__Genius 12866 points

Taking this to Email discussion

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DS90UB927Q-Q1: configuration to work with 928