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Author Topic: ME813A-WH50C Display - Controlling the backlight  (Read 1053 times)

jberkhout

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ME813A-WH50C Display - Controlling the backlight
« 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.
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FTDI Community

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Re: ME813A-WH50C Display - Controlling the backlight
« Reply #1 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

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
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jberkhout

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Re: ME813A-WH50C Display - Controlling the backlight
« Reply #2 on: June 14, 2018, 12:32:53 PM »

Thank you very much!
This is very helpful!
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jberkhout

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Re: ME813A-WH50C Display - Controlling the backlight
« Reply #3 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.
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Rudolph

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Re: ME813A-WH50C Display - Controlling the backlight
« Reply #4 on: July 02, 2018, 05:19:02 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.
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