Guys I need your counseling or any tip to this:
I want to connect a TFT lcd controlled by SPI to the Yun, using the linux enviroment to control it, just like this project does (here they use arietta g25):
Do you think it can be done on the Yun?
I know that Atheros has the SPI pins connected to atmega spi, so I can access them (I wont get involved with sketches, everything will be done by the Atheros). I know that this tft lcd needs also analog, but I think I can make it work without those (Im not interested on the touch feature).
On the software side, I must compile those lcd drivers for the openwrt, I think this is the harder obstacle.
Yes, if you are not interested in the touch screen, you won't need the analog connections.
I'm not an expert in the field, but looking at the SPI configuration file on the site you reference, it looks like it is accessing some dedicated SPI hardware. The SPI interface on the AR3391 does not have any special hardware behind it, my understanding is that it bit-bangs the SPI control signals over GPIO lines. You will have to look at the Yun schematic to figure out which lines they are, and also which additional GPIO lines you will need to set up to activate any level shifters or other gating circuitry to route those SPI signals to the ICSP connector. You will also have to make sure that the sketch in the '32U4 processor does not set any of the SPI outputs but leaves them as inputs to prevent any conflicts with the AR3391's use of those lines.
I think you should be able to get it to work, but I agree that getting the software to work on the Linux side will be the difficult part.
Thanks for the input Shape, I'll check those spi gpios and see if they are dedicated hardware or just bitbang.