FTDI Community

General Category => Discussion - Software => Topic started by: jberkhout on June 14, 2018, 09:09:06 AM

Title: ME813A-WH50C Display - Controlling the backlight
Post by: jberkhout on June 14, 2018, 09:09:06 AM

Hi,

The FT800 provides a PWM output to adjust the brightness of the display’s LED array.
I’m new to this platform, how do I control the backlight, say with a slider?

Thank you very much for helping me out.

Regards from the Netherlands.

Title: Re: ME813A-WH50C Display - Controlling the backlight
Post by: FTDI Community on June 14, 2018, 11:32:43 AM

Hello,

Thanks for your question.

Curiously your previous forum post from this morning mentions the FT813, so I will run with the assumption you are using this and not the FT800, please correct me if I am wrong.

The Registers that control the FT813's backlight are covered in Section 3.6 of the FT81x Programmers guide:
http://brtchip.com/wp-content/uploads/Support/Documentation/Programming_Guides/ICs/EVE/FT81X_Series_Programmer_Guide.pdf (http://brtchip.com/wp-content/uploads/Support/Documentation/Programming_Guides/ICs/EVE/FT81X_Series_Programmer_Guide.pdf)

There is a small example included in section 5.17 for CMD_MEMWRITE which covers changing the backlight intensity.

Re-rewriting the applicable registers based on the position of a slider should be easily achievable.

Best Regards,
FTDI Community

Title: Re: ME813A-WH50C Display - Controlling the backlight
Post by: jberkhout on June 14, 2018, 12:32:53 PM

Thank you very much!
This is very helpful!

Title: Re: ME813A-WH50C Display - Controlling the backlight
Post by: jberkhout on June 30, 2018, 02:53:24 PM

This is how I control the backlight, I hope it helps somebody.

Code: [Select]

void FT813::SetBacklight(ft_uint16_t brightness)
{
    brightness = brightness * brightness / 255;
    if (brightness > 255)
        brightness = 255;
    if (brightness < 16)
        brightness = 16;
    Wr16(REG_PWM_DUTY, brightness); // Brightness
}

Regards,
Jack.

Title: Re: ME813A-WH50C Display - Controlling the backlight
Post by: Rudolph on July 02, 2018, 05:19:02 PM

Quote from: jberkhout on June 30, 2018, 02:53:24 PM

This is how I control the backlight

Why? What purpose serves that calculation?

I just use a 8-bit memory write:
FT8_memWrite8(REG_PWM_DUTY, 0x10);

And the valid range is 0...128.

Title: Re: ME813A-WH50C Display - Controlling the backlight
Post by: jberkhout on January 27, 2023, 08:07:34 PM

It regulates the brightness more according the non-linear sensitivity of the eye, so say 50% appears more like 50% for the eye.

Title: Re: ME813A-WH50C Display - Controlling the backlight
Post by: FTDI Community on January 30, 2023, 09:46:35 AM

Hello,

Please post any new or replies on the BRT Community as Bridgetek support EVE products:

http://www.brtcommunity.com/

Best Regards,
FTDI Community