i.MX ProcessorsのトピックRe: Display Flickering

Display Flickering

Nagesh — Tue, 21 Aug 2012 12:23:25 GMT

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.

Re: Display Flickering

admin — Wed, 22 Aug 2012 13:24:52 GMT

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

Re: Display Flickering

Nagesh — Wed, 22 Aug 2012 17:27:04 GMT

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?

Re: Display Flickering

YuriMuhin_ng — Thu, 23 Aug 2012 03:08:46 GMT

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).

Re: Display Flickering

Nagesh — Fri, 24 Aug 2012 06:32:43 GMT

Thank u...Problem has been solved

Re: Display Flickering

kishorepoojari — Fri, 16 Oct 2015 06:33:40 GMT

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

Re: Display Flickering

ervingattis — Fri, 16 Oct 2015 07:08:49 GMT

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.

Re: Display Flickering

kishorepoojari — Fri, 16 Oct 2015 12:33:26 GMT

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