One of [Sprite_tm]’s colleagues recently challenged him to connect a small LCD touch screen to a Raspberry Pi. Sadly, [Sprite_tm] has yet to take delivery of a Raspberry Pi, but he did manage to connect an LCD to a Linux board without video capabilities.
Because [Sprite_tm]’s display has a 16-bit parallel interface, and 16 GPIO pins are hard to come by on the Carambola Linux board, a few shift registers had to be brought into the build to make the LCD work. These shift registers are connected to the Carambola board via an SPI interface; a very simple way to connect all the LCD pins to the Linux board.
Of course, there’s no way for Linux to speak to the LCD without a kernel driver; [Sprite_tm] wrote a framebuffer driver so the LCD can be used as a console, an X session, or used by any other program that can write to a framebuffer device.
Like all good driver authors, [Sprite_tm] is giving away the patch to enable SPI-ified LCD panels on the Carambola along with the shift register schematic. With any luck we’ll also see the Raspi drivers when [Sprite_tm] takes delivery of his Raspberry Pi.
11 thoughts on “[Sprite_tm] Connects An LCD To A Tiny Linux Board”
SPI is a very simple way to connect all the LCD pins to the Linux board. It’s also quite slow, too.
and that’s BEFORE the shift registers.
Not necessarily. The SPI-interface on the Ralink-chip on the Carambola can run up to 50MHz, which is plenty quick. Unfortunately, it does seem to have a lot of overhead wrt setting up transfers, which slows down everything quite a bit… The Pi could do better there, iirc that chip can do a DMA-transfer to the SPI-interface which should be lots quicker.
Dang SpriteTM you always rock it out! Don’t ever stop :)
Sadly, the DSI Interface is directly connected to the GPU, which needs a binary blop to run properly since it’s closed source.
However, the foundation plans to release a LCD display in the future so we can expect a driver then which would make it possible to use standard LCD displays for smartphones . Anyway, until this happens there is nothing to do but to wait.
I’ve always made “Can it play Monkey Island?” my personal test of a machine’s usefulness. Very nice!
I LOVE the Monkey Island series. They are always comical and I will still play them over again every once in a while and find myself chuckling again. The Monkey Island series and Super Metroid are my all time favorite games.
I love the Monkey Island!
Sprite_tm, you’re a hack-factory. Always good stuff and in topics I’m interested in.
what a great game. Back when games only had single player, they needed a great storyline. Unlike the same old Call of duty crap that comes out every year.
You fight like a dairy farmer.
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