Hi Rob, would a PIC with PPS help?
Matt.
On Tuesday, April 28, 2015 at 4:44:52 AM UTC-4, RobH wrote:
>
>
> Hi guys,
>
> Recently I picked up an old project again which uses among others a
> graphical LCD. I think I did put the board aside because I could not get
> it to work properly. It turns out the that the (8) datalines to the GLCD
> are in the wrong sequence. Since the GLCD library uses the full 8 bits
> of a port I do not see a better way to solve this problem (apart from
> changing the hardware) than to insert code to reverse the bits in the
> data byte. Now I'm looking for a good algorithm. I found several pretty
> efficient procedures for ASM and also a few for C/C++. For now I'm using:
>
> > function reverse_bits(byte in data) return byte is
> > const byte lookup_table[16] = {
> > 0,8,4,12,2,10,6,14,1,9,5,13,3,11,7,15 }
> > var byte temp
> > temp = 16 * lookup_table[data & 0x0F]
> > temp = temp + lookup_table[data >> 4]
> > return temp
> > end function
>
> This looks elegant and seems to work OK, but it may not be very efficient.
> Suggestions???
>
>
> I may not be the only one with the mentioned mistake with the datalines,
> but it would also make the GLCD library more flexible when there are
> more choices for the datalines. Reversing the bits could be one option,
> the use of 2 half ports or 8 individual pins could be other options
> (like with the character-LCD libraries).
>
> Regards, Rob.
>
> --
> *Rob H*amerling - http://www.robh.nl
>
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