FTDI Community
General Category => Discussion - Software => Topic started 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.
-
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
-
Thank you very much!
This is very helpful!
-
This is how I control the backlight, I hope it helps somebody.
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.
-
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.
-
It regulates the brightness more according the non-linear sensitivity of the eye, so say 50% appears more like 50% for the eye.
-
Hello,
Please post any new or replies on the BRT Community as Bridgetek support EVE products:
http://www.brtcommunity.com/
Best Regards,
FTDI Community