topic Re: How to check if it is a VBlank period in i.MX Processors

How to check if it is a VBlank period

zakio — Wed, 07 Oct 2020 07:06:18 GMT

I am using MIPI-DSI on i.MX 7Dual.
I'm trying to switch from HS mode to LP mode while drawing and read the registers on the LCD panel. I would like to do this during the Vblank period. Is there a way to check if it is during the Vblank period?

Re: How to check if it is a VBlank period

igorpadykov — Thu, 08 Oct 2020 00:46:05 GMT

Hi zakio

>. Is there a way to check if it is during the Vblank period?

sorry this is not possible as LPDT (enter to LP mode) area is not within VSYNC as described in
Figure 13-36. Stable VFP Area Before Command Transfer Allowing Area

i.MX 7Dual Applications Processor Reference Manual

Best regards
igor

Re: How to check if it is a VBlank period

zakio — Thu, 08 Oct 2020 01:02:25 GMT

Hi igor

Thank you for your reply.
Does that mean I can't switch from HS mode to LP mode while drawing (from VSync to the next VSync)?
During the VBlank period, I'm thinking of stopping drawing and then switching.

Best regards

zakio

Re: How to check if it is a VBlank period

igorpadykov — Thu, 08 Oct 2020 04:57:46 GMT

Hi Zakio

please refer to Figure 13-36. Stable VFP Area Before Command Transfer Allowing Area-

it shows area where it is possble:

"Only this area ..command through LPDT or HS (register configuration)"

i.MX 7Dual Applications Processor Reference Manual

Best regards
igor