DS90UB927Q-Q1: FPD-LINK question

Hi Alex,

Could you provide a little more info? 

1. What is the back channel speed setting?

2. What is the I2C speed setting?

3. How many bytes are in one touch sequence?

Best Regards,

Charley Cai

Hi Charley

1. What is the back channel speed setting?

2. What is the I2C speed setting?

i can't find the setting in spec, please refer to my attached resister setting.

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/138/Code.7z

3. How many bytes are in one touch sequence?

66byte in one touch sequence.

Hi Charley

Please refer to the attached data, 

The data is that the I2C at 927 side and 928 side.

The I2C speed of the Touch panel should be set as 400KHz, but i measure 400KHz at 927 side and 256KHz at 928 side.

How to set the same speed at both side?

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/138/FPD_2D00_link_5F00_check.7z

Hi Alex,

To change the 928 I2C speed, you can set the SCL high time and SCL_Low time registers. 0x26 and 0x27.

Please try to set 0x26 = 0x18 and set 0x27 = 0x20. 

Best Regards,

Charley Cai

Hi Charley

I try to set the 0x26=08, 0x27=1A, and the I2C of 928 is around 400KHz which is the same as 927 side.

Then the drag delay phenomenon disappears and keep smooth.

So is the value 0x26=08, 0x27=1A okay? or i need to evaluate the other parameters.

Thanks a lot , Alex

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