18bit lcd interface: can I reuse unused pins?

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1

Hi,

This is a generic OMAP question not specific to beagleboard, but I
hope some would help me out here.

I need only 18bits out of the 24bit available for my LCD so, I plan
to leave the least significant bits of each color out, as expected.
But, can those unused pins be muxed to the GPIO setting with out
affecting the other LCD pins?

  Appreciate your time.

--Krishna/.

2

Hi!

why not? Every pin is configured independently. Look, first you configure LCD controller for a specific output configuration, but MUX controller does not know about LCD :). So it is your commitment to setup MUX properly so the LCD controller could output it’s signals…

regards,
Max

2010/4/8 Krishna <sagiraju@gmail.com>

3

okay. Thanks for the reply.

--Krishna/.

4

Of course you can use the pins for something else (like GPIO).

I need only 18bits out of the 24bit available for my LCD so, I plan
to leave the least significant bits of each color out, as expected.

But something else: it is a common mistake on OMAP3 to leave the LSB's
out going from 24bit to 18bit. For some reason TI chose to leave the
MSBs out instead... Check the TRM.
Then you need to configure the DSS for 18 bits - but you can use DSS
features like spatial and temporal dither.