Juggernaut
Posts: 7
Joined: Sat Mar 21, 2015 4:50 pm

SPI TFT without D/C pin (9-bits SPI)

Sat Mar 21, 2015 5:13 pm

hello guys,
I have ili9340 tft-lcd, and i plan to setup it as my raspi's mini display, with Notro's FBTFT module.
and i check the FBTFT support LCD list: https://github.com/notro/fbtft/wiki/LCD-Modules
it does not support ili9340 TFT without D/C pin.

any comments for this?
thanks!!!
Luke, use your force!

Juggernaut
Posts: 7
Joined: Sat Mar 21, 2015 4:50 pm

Re: SPI TFT without D/C pin (9-bits SPI)

Mon Mar 23, 2015 4:08 pm

Experts, help me :D
Luke, use your force!

msperl
Posts: 344
Joined: Thu Sep 20, 2012 3:40 pm

Re: SPI TFT without D/C pin (9-bits SPI)

Thu Mar 26, 2015 9:13 pm

From what I have gleaned from the driver the reason is that the device is actually 9-bit spi, which is not supported by the linux framework as is, but has an 8-bit spi + d/c (d=data, c=command) to emulate the same thing.

Note also that the lossi mode (9bit mode) of the hardware spi has some special functions that require specific code to work as is - the spi-bcm2708 driver contains only marginal support for writing to 9-bit spi, but no support for 9-bit reads.

That is why notro implemented the 8bit +dc alternative as default.

So you will have to accept that extra dc-pin...

Martin

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