Just receive a cool new product over at Adafruit: a 3.5" NTSC-compatible TFT lcd screen (they also have a lilliputian 1.5" model). It was manufactured to be used with the RPi but it seemed better suited for a Uzebox portable project I had in mind for a while! I quickly plugged it in an a picture came in instantly...but alas it is not stable, most probably due to the non-standard timing used by the kernel . I plugged in my SNES to cross-check and same result. Though it works perfectly with standard signals (plugged it in my DVD player and watched Star Wars a bit ). I'm wondering now if it would not be possible to generate full standard signals while avoiding the usual interlacing artifacts...will think about it.
I tried some month before to connect a 4 inch analogue TFT (AO40CN01 with driving board PMDVB56R) to the EUzebox - it works, but the low horizontal resolution 320 x 240 was a problem... The picture was not so clear as on a TV
driving board
PMDVB56R_driving_board.jpg (38.85 KiB) Viewed 3898 times
my test board with TFT and assembled SCART connector, driving board on back side
AO40CN01_witth_RGB_SCART.jpg (20.36 KiB) Viewed 3893 times
The resolution of the TFT from adafruit is the same. I'm curious about your results...
I thought of connecting a standard "TTL" QVGA display to the uzebox to get a portable arcade. There are hundreds of such displays - TFT and OLED - out there, at extreme low prices. You even can dismantle old color display cellphones to get such a display for free. They usually have 666 or 888 color inputs, HSYNC and VSYNC separated, and pixel clock.
So some minimal tweaking is required to generate a separate VSYNC. The pixel clock can be automatically generated by the ATmega644 on its clock output. Frame rate is almost always 60Hz, so not problem with current timing, horizontal timing has to be tweaked only a little. To reach full white levels with uzebox, lower bits have to repeat the values of the higher bits:
Janka wrote:I thought of connecting a standard "TTL" QVGA display to the uzebox to get a portable arcade. There are hundreds of such displays - TFT and OLED - out there, at extreme low prices. You even can dismantle old color display cellphones to get such a display for free. They usually have 666 or 888 color inputs, HSYNC and VSYNC separated, and pixel clock.
Very good idea, but we have to recompile all games in this case...
A while ago someone managed to tweak the kernel timing to support such displays, so it's quite feasible: http://uzebox.org/forums/viewtopic.php?p=1220#p1220 As harty said, one would have to recompile all games for it but I guess that's the price to pay to have the coolest retro portable in town.
Harty123 wrote:Very good idea, but we have to recompile all games in this case...
I thought that to be the easiest part of it. Most complicated is to make a nice casing for it.
EDIT: I'd think unusual devices and using arcade boxes with JAMMA connector is the right way to go. As Harty123 wrote elsewhere, a lot of people would say "I can play Donkey Kong on my NES". To me that means to make uzebox attractive, it has to be different from NES, and different from 2000' style PC based home entertainment. That's why games with unusual controllers are so popular.
. I plugged in my SNES to cross-check and same result. Though it works perfectly with standard signals (plugged it in my DVD player and watched Star Wars a bit 
). I'm wondering now if it would not be possible to generate full standard signals while avoiding the usual interlacing artifacts...will think about it.
