Display Flickering

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Display Flickering

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Nagesh
Contributor I
We are using the i.MX233 processor in our design. As far as the finctionalities are concerned everything seems to be working fine.We have observed a peculiar problem with LCD.When we shake the device OR move the device fast in horizontal direction, the screen updates(as flickering) are visible to bare eyes.We are not able to identify what is causing this problem. The same behaviour also observed on i.MX233 evaluation Kit.
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ervingattis
Contributor I

As per my experience you must try the high LCD refresh rate. It must be 85Hz or greater.

Use this one Refresh rate= pixel clock/number of clocks per frame.

It is also called stroboscopic effect because of external light flickering.

For this the display refresh frequency should not be a multiple of the frequency of light.

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kishorepoojari
Contributor III

Hello Ervin ,

  We are facing flickering problem only when control is transferred  from bootloader to O.S , where frame buffer starting address will be switched (From BL to OS).

Once KIOSK application is up their is no flickering is observed . Is their any solution to avoid the flickering while switching the frame buffer starting address.

Regards,

Kishore P

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Nagesh
Contributor I

Thank u...Problem has been solved

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kishorepoojari
Contributor III

Hello Nagesh,

   We are using imx233 processor and LCD display with the spec:

Resolution:320*240

Bus width:16bit

pixel clock:5 to 6.8MHz

   LCD Display will start to flicker when control is transferred  from bootloader to O.S , where frame buffer starting address will be changed. Please tell me what solution you are followed  to overcome your problem , which may help  to solve our problem.

Regards,

Kishore P

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YuriMuhin_ng
Contributor I

Perhaps we have so called stroboscopic effect because of external light flickering.
In such case display refresh frequency should not be a multiple of the frequency of light (60 hz).

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Nagesh
Contributor I

HW to increase refresh rate to 85Hz??

Specs of LCD which i am using:

Resolution:320*240

Bus width:16bit

pixel clock:5 to 6.8MHz

I tried with increasing pixel clock upto 8MHz then also Flicker problem is still present.The same problem is even present in the i.MX233EVK.

Refresh rate= pixel clock/number of clocks per frame

I increased the pixel clock which in turn increases the refresh rate.Then also  problem was still there.

Is there any other parameter to increase refresh rate or is it some other parameter which is causing this problem?

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admin
Specialist II

You need use high LCD refresh rate. Try use 85Hz or higher.

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