topic Re: Screen refresh timing in i.MX Processors

Screen refresh timing

Kazuma_Sasaki — Wed, 19 Jun 2019 13:27:17 GMT

From i.MX 6Solo/6DualLite Applications Processor Reference Manual, Rev. 4, 07/2018

38.1.2.1.6.1 Screen Refresh
• The refresh rate may vary within a predefined range. Within this range, the rate is
dynamically adjusted to the content update rate.

Reference manual mentioned that IPU will change display's refresh rate dynamically.

Let me confirm two things with you.

Q1. What is meaning of above description? I suppose if DMFC has not updated every frame, refresh rate will be down. is it right?

Q2. How do I know current refresh rate? does any register indicate us the current refresh rate?

Best Regards,

Kazuma Sasaki.

Re: Screen refresh timing

gusarambula — Tue, 02 Jul 2019 19:26:37 GMT

Hello Kazuma Sasaki,

My apologies for the delay.

I was reviewing the screen refresh characteristics and (Q1) the refresh rate is adjusted according to the HSYNC, VSYNC and pixel clock, which determines the resolution of the frame. It is not dependent on the content itself (unlike a decoder, for example, that optimizes compression depending on how much the content changes from frame to frame).

As for how to know the current refresh rate (Q2) there is not a register that has the refresh rate although you could calculate it from the display parameters.

I hope this information helps!

Regards,

Re: Screen refresh timing

Kazuma_Sasaki — Wed, 03 Jul 2019 12:55:02 GMT

Hello gusarambula,

Okay, I got it. I appreciate your support.

Best Regards,

Kazuma Sasaki.