Re: A86: Contrast
[Prev][Next][Index][Thread]
Re: A86: Contrast
i wrote a contrast changer a while back heres the code. hope it helps.
start:
call _clrLCD ;clear the screen
call _homeup ;put cursor in top left corner
getkey:
call _getkey ;start getkey routine
cp kUp ;check for addition key
jp z,cadd ;if addition key is pressed, jump
cp kDown ;check for subtraction key
jp z,csub ;if it is pushed, jump
cp kExit ;check for enter key
jp z,exit ;if pushed, jump
jr getkey ;if no key is pushed, repeat steps
cadd:
ld a,($C008) ; load contrast value
inc a ; increase the contrast
ld ($C008),a ; write it back to memory
out (2),a ; and to the port
jr start
csub:
ld a,1
ld a,($C008) ; load contrast value
sbc a,1 ; decrease the contrast
ld ($C008),a ; write it back to memory
out (2),a ; and to the port
jr start
exit:
call _clrLCD ;clear the screen
call _homeup ;return the cursor
ret ;return th ti-os