topic Re: evkmimxrt1060_elcdif_rgb performance issues in i.MX Processors

evkmimxrt1060_elcdif_rgb performance issues

patriciocohen — Tue, 03 Oct 2023 19:42:13 GMT

Hi guys,

I'm testing a custom PCB with the IMXRT1062 which is connected to a LVDS screen through the SN65LVDS93A (RGB to LVDS converter IC). The board has the HYPERRAM IC S27KS0642GABHV020 working with a 200MHz clock connected to FLEXSPI2, place where the LCD framebuffer is located.

At the moment I have been able to try the evkmimxrt1060_elcdif_rgb example, but the FPS I get is no way near 60.Can you please tell me what can I do for increasing its performance?

I'm using release debug configuration. Attached you can find the project as a zip file.

The display timing information is below.

Thank you.

Patricio

Re: evkmimxrt1060_elcdif_rgb performance issues

patriciocohen — Wed, 04 Oct 2023 17:30:46 GMT

kerryzhou, can you please help me?

Best regards,

Patricio

Re: evkmimxrt1060_elcdif_rgb performance issues

kerryzhou — Thu, 05 Oct 2023 07:50:35 GMT

Hi @patriciocohen ,

Thanks for your trust, and sorry for our later reply becase we are in the China National Day vocation before 10.7, we will back to work from 10.8, as I receive the email you AT me, so I simply repy you at first.

In fact, what the FPS your LCD can be supported, it can be calculated, it is determined by your used LCD.

Here is an example:

------------------------

Just to the RT1060 LCD, it can support the 60FPS.

RT1060PCLK max frequency is 75Mhz.

take an example:
Resolution is 240*320, RGB565=2B.
Then, you can refer to your used LCD to calculate the frame clock.
frame clock=(VSPW+VBP+LINE+VFP)*(HSPW+HBP+HOZVAL+HFP)
Then, the FPS=75Mhz/fram clock.
Take an example of one LCD:
(240+10+80+70)*(320+3+10+10)=400*343=137200hz
the FPS=75Mhz/137200hz=546

-------------------------------

But your LCD is large:1024*600,

I calculate it, use the max data in your table, and te 75MHZ PCLK, you can use about 42 FPS.

It's really can't upto the 60fps, it is determined by your used LCD, so large.

About the improvement, you can refer to this picture:

But it still can't improve it to 60 FPS, as the hardware already limit it.

Wish it helps you!

Best Regards,

Kerry

Re: evkmimxrt1060_elcdif_rgb performance issues

patriciocohen — Mon, 09 Oct 2023 23:13:57 GMT

Thank you Kerry.

Given the timing info I posted, can you please help me fill the constants for getting the max performance?

Thank you

Patricio

Re: evkmimxrt1060_elcdif_rgb performance issues

kerryzhou — Tue, 10 Oct 2023 02:32:44 GMT

Hi @patriciocohen ,

Thank you for your updated information.

In fact, I already help you to calculate it in the last email:

------------------------

Just to the RT1060 LCD, it can support the 60FPS.

RT1060PCLK max frequency is 75Mhz.

-------------------------------

But your LCD is large:1024*600,

I calculate it, use the max data in your table, and te 75MHZ PCLK, you can use about 42 FPS.

Do you mean the 42 FPS is not the max performance you want?

Which detail performance parameter you need now?

Best Regards,

kerry

Re: evkmimxrt1060_elcdif_rgb performance issues

patriciocohen — Tue, 10 Oct 2023 12:36:01 GMT

Hi Kerry,

Thanks for your reply.

With your answer I already know I will not be able to get 60fps. However, I will like to get the maximum performance with this LCD. The display doesn't work with a clock greater than 63MHz, so that is the maximum freq I can use with the elcdif. Which values would you use for maximizing performance? 42 FPS is ok, but I don't know if this can be achievable with 63Mhz max clock. Even if 42 FPS are not achievable, it doesn't matter, I just want to be sure I will work with the maximum performance possible.

I will appreciate very much if you can detail the calculation for the max FPS of my display given that its clock can be 63MHz max.

With the table I posted in the first message, please help me with the defines below with "?".

Thank you very much.

#define APP_IMG_HEIGHT 600 // Display panel height

#define APP_IMG_WIDTH 1024 // Display panel width, pixels per line

#define APP_HSW ?

#define APP_HBP ?

#define APP_HFP ?

#define APP_VSW ?

#define APP_VBP ?

#define APP_VFP ?

Re: evkmimxrt1060_elcdif_rgb performance issues

kerryzhou — Wed, 11 Oct 2023 06:09:46 GMT

Hi @patriciocohen ,

This application note will help you:

https://www.nxp.com/docs/en/application-note/AN12302.pdf

Give you 2 example, you will be clear:

So, your situation is:

#define APP_HSW 140

#define APP_HBP 160

#define APP_HFP 160

#define APP_VSW 20

#define APP_VBP 23

#define APP_VFP 12

The data mainly use the typical data.

Wish it helps you!

Best Regards,

Kerry

Re: evkmimxrt1060_elcdif_rgb performance issues

patriciocohen — Sun, 15 Oct 2023 19:48:43 GMT

Thank you kerry