Main > Raspberry Pi & Dev Board
RPi 2 and an SPI-based 4" LCD screen (and MAME)
MacGyver:
Even running pure kernel based FB drivers with DMA and clocking mine at 60mhz makes it only 80% usable. In the end it looks like SPI based screens need to be 320x240 or less to work at full speed.
I haven't given up yet, well I did sort of, I ordered an HDMI-based 5", but I think if I can overclock the SPI I might be able to push more data to the old SPI screen. (i don't really think it's going to work, so anyone thinking of using a 480x320 SPI-based screen, save your money, go lower res or HDMI)
acme64:
what if you don't run at native resolution? does the LCD scale?
MacGyver:
No, at least not on the factory Raspian image or a new Rasipian using native FB with DMA. It just displays in the middle as a tiny moving image, and the framerate still sucks even when the only thing moving is a tiny screen. If I send a smaller res, it just white stripes the dead area. My 5" HDMI works perfect and at full speed.
dgame:
Okay, I finally got MAME to run on the 3.2" 320x240 TFT and my initial results are similar to MacGyver.
I tested with the circus ROM and on the HDMI output it is 100%. However on the TFT circus throttles from 80% to, even over, 100%.
I did not do any tweaking yet. Just got it to show on the TFT.
I broke my first TFT touch screen and my replacement came yesterday.
The first TFT screen is cracked but still works. The cracks make the touch surface useless though.
If anyone has a Raspberry Pi and wants to experiment with MAME on the TFT PM me and I can send you the cracked screen for free.
The 3.2" 320x240 TFT screen can be purchased new ($12.45 shipped from in US) from here: http://www.banggood.com/3_2-Inch-TFT-LCD-Display-Module-Touch-Screen-For-Raspberry-Pi-B-B-A-p-1011516.html
Even if we can't make it run MAME 100% it still could be a nice touch screen for projects. Could make a sweet mini jukebox or media player. You can also use the HDMI output at the same time.
MacGyver:
Duhjoker said he was able to get good speeds with a non stock FB (framebuffer) copy driver named rpi-fbcp, I haven't tried it as I don't use the SPI based screen anymore, but you might want to give it a whirl.
If it does work out better please report back; there might be hope yet.
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