SN65DSI83: sn65dsi83 VOD

Terry Wu2

Part Number: SN65DSI83
Other Parts Discussed in Thread: DSI-TUNER

Hello Sir,

Would you advice how to modify DSI83 VOD due to some LCD need 400mV(min) ? Is there register setting sequence need to care ?

If possible,pls share your VOD waveform for our reference .

TKS !

Below is LVDS output and change 0x19 3:2 to "11" . Don't see VOD change.

Below is change termination from default 200 ohm to 100 ohm.

0x19 3:2 still "11" and disconnect LCD panel .

over 6 years ago

0 Ikechukwu Anyiam over 6 years ago

TI__Mastermind 35130 points

Hi Terry,

These registers should be set during the initialization sequence in the datasheet in "Init seq 5".

However, I believe 400 mV differential may be out of specification for this device, because the LVDS CLK cannot reach this level even when 0x19.3:2 = 11. Can you share the datasheet for the display?

Regards,
I.K.

0 Terry Wu2 over 6 years ago in reply to Ikechukwu Anyiam

Expert 2110 points

Hello I.K.

Thanks your comment !TM080JDHP96-00-Final-SpecV2 0 20171018.pdf

I attach LCD spec for you reference.

VID up to 600mV (max)

TKS !

0 Terry Wu2 over 6 years ago in reply to Terry Wu2

Expert 2110 points

Hello I.K.

I also need to make sure DSI83 VOD measurement when disconnect LCD panel .

Add 100/200 ohm resistor across dsi83 output P/N pin depends on dsi83 internal terminator .

Then use high frequency differential probe to scope VOD, right ?

TKS !

0 Ikechukwu Anyiam over 6 years ago in reply to Terry Wu2

TI__Mastermind 35130 points

Hi Terry,

Your display datasheet says the range of VID is 200 to 600mV. The default configuration of 0x19.3:2=01 and 200ohm termination should work fine as it's within this range.

What exactly is the issue you're having with the display?

Regards,
I.K.

0 Terry Wu2 over 6 years ago in reply to Ikechukwu Anyiam

Expert 2110 points

Hello I.K.

The LCD display is OK but have flicker issue like the LCD spec you see .

We find the common mode voltage is out of LCD spec . We'll try to modify register to try again.

May I know correct VOD measue method for DSI83 only without connecting LCD panel ?

How to determine DSI83 100/200 ohm near-end termination ?

Many thanks !

0 Ikechukwu Anyiam over 6 years ago in reply to Terry Wu2

TI__Mastermind 35130 points

Hi Terry,

You can use a high frequency differential probe to scope VOD, yes.

However, I don't see how the common mode voltage is out of the LCD specification either. Your LCD datasheet says VCM should be within 1 to 1.8-Vid/2 V. Our DSI83 datasheet has VCM typically 1.25 V when 0x19.6 = 0, which is within specification.

The flickering issue is probably related to something else. Please see below:

1. Ensure that you're following the initialization sequence in the datasheet.
2. Please fill out the settings you're using in the DSI-Tuner tool and either send me the .dsi file or post screenshots of both windows here.

Regards,
I.K.

0 Terry Wu2 over 6 years ago in reply to Ikechukwu Anyiam

Expert 2110 points

Hi I.K.

May I have your email address to discuss ? Many thanks your help !

0 Ikechukwu Anyiam over 6 years ago in reply to Terry Wu2

TI__Mastermind 35130 points

Hi Terry,

Sorry for the delay. You can email me at i-anyiam@ti.com

Regards,
I.K.

0 Ikechukwu Anyiam over 6 years ago in reply to Ikechukwu Anyiam

TI__Mastermind 35130 points

Hi Terry,

I will go ahead and close this thread for now. Please let me know if you continue to have issues though.

Regards,
I.K.

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SN65DSI83: sn65dsi83 VOD