Good quality 3.5" HDMI screen? (not happy with KeDei or MPI3508)

Raspberry Pi hardware discussion (including peripherals)
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Good quality 3.5" HDMI screen? (not happy with KeDei or MPI3508)

Post by blci » Fri Jan 05, 2018 12:51 pm

Recently got two different HDMI displays for testing with Raspberry Pi 3 Model B and EmulationStation:
- KeDei version 1.1 2017/7/1 with RTD2660H, H4E25G1 GH15B TAIWAN
- MPI3508 V1.0 with RTD2660H, H6E90G1 GH25B TAIWAN

and they seem to be functionally quite identical, but unfortunately neither of them felt good.

The two problems I found were
- 1) the pixel response time on both of the panels seem noticeably weaker compared to Adafruit PiTFT 2.8" (, and there's a bit of ghosting/smearing left behind in panning motion. This is something that I might not have paid too much attention to, except that I had both Adafruit PiTFT and the KeDei screens running side by side, where the difference was noticeable, so now it's bugging me a bit.
- 2) it looks like neither the KeDei or the MPI3508 screens implement proper vsync updating, but even when vsync is enabled in the Raspberry Pi EmulationStation programs, the updates on the screen occur with visible tearing. Swapping over to an Elecrow 7" HDMI display ( ... B01GDMDFZA), I don't see any vsync tearing, which suggests that this might not be a software configuration issue, but the KeDei/MPI3508 displays lack vsync.

I'm thinking I might roll with the SPI-based Adafruit PiTFT and use this driver for good performance if I don't come up with a HDMI display that I'd particularly like. As far as image quality goes, I like the pixels on the Adafruit one. (Although one can dream of an 3.5" 320x240 OLED display popping up one day :) What's your favorite/best quality 3.5" HDMI 320x240 or 480x320 screen? Any experiences with migrating over to using DPI screens in ~3.5" form factor?

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Re: Good quality 3.5" HDMI screen? (not happy with KeDei or MPI3508)

Post by salami738 » Wed Feb 21, 2018 11:09 am

Kite is using 3.5inch dpi screens.
The cheap one has 320x240, the better one has 640x480.

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