LCD display and backlight

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VK3KYY
Posts: 7478
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

LCD display and backlight

Post by VK3KYY » Mon Jan 03, 2022 12:19 am

The LCD display has the same usable resolution as the GD77/DM1801, 128 x 64 pixels, however the phyical display aspect ratio is more rectangular than the GD77, and the pixels are rectangular rather than square

This is very obvious on the satellite polar screen, which draws a circle, becuase the circle looks like an elipse.

We are using the bitmap fonts, and this results in the text looking more bold than on the GD88, and much more bold than the official firmware font.

We may be able to make some minor adjusments to the bitmap font, but I don't personally have a problem with the font being more bold, and I think the official font is less readable, so we are not likely to make any major changes to the font.

It may be possible to slighly correct the satellite polar display, but its also not a big problem, and it is more readable being eleptical.



The backlight intensity is not adjustable in the official firmware, but I have tried to make it adjustable in this firmware, like on the GD77.

However, there are some limitations to this because we can only use relatively low frequency of PWM as the display electronics do not seem able to handle frequencies above a few hundred Hertz.

There is also a strange problem when selecting very low display backlight levels, e.g. 2 or 3% because the hardware seems to not like very small short pulses of PWM

Also on some radios if you listen carefully the PWM signal can be heard on Tx. But it is inaudible on most radios, so is not a big problem, and there is no possible firmware solution to this

I1KDO
Posts: 27
Joined: Sat Nov 16, 2019 7:49 am

Re: LCD display and backlight

Post by I1KDO » Fri Jan 21, 2022 5:45 pm

I check on day and night i like nice BOLD for my eyes

73
Lorenzo

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