Charlie-plexing

[Boater]

Hi Richard
Thanks again for some great information.
Got the 20 Leds working fine. Tried the pauseus 1200 in the code and they are very dim with 100 ohm resistors.
Found out that in the tris values where you have a pair you leave both alone if the port.4 (16) is involved.
I have been looking through the PBP compiler manual but can not find any reference to the $e0 or the $f0.
Does the $e0 remove the mask from all the upper 4 bits? and are there any more masking commands?
I am thinking of doing a 30 led charlieplex, I have the layout for it.
They are just on a breadboard at the moment and until I can design a good pattern that is where they will stay.
I would like to know more about your last code set but I think I will need to wait until I upgrade and get a 16f1825 pic.
Regards
Jim

[richard]

$e0 = binary 11100000
$f0 = bin 11110000

logical function AND (&) goes like this

a b a&b
0 0 0
0 1 0
1 0 0
1 1 1

logical bitwise function OR (|) goes like this
a b a&b
0 0 0
0 1 1
1 0 1
1 1 1

masking clearing and setting bit/s in a var can be accomplished this way

eg if a = %11111111 (255 or $ff)

then a&$e0= %11100000

then a | 12 = %11101100

see bitwise in book