June 12, 2005

PROGRESS WITH LIQUID CRYSTAL DISPLAY

I have developed several subroutines which have been tested and work pretty well.
dspyon - turns display on showing what is in memory
dspyof - turns display off
strtln - specifies line in mem for top of display
shftwd - my routine to shift a byte of data serially to DB0-DB7
write - after page, y-addres, and number of writes have been set
and content of byte to be written have been set, it
writes up to 64 byte-columns (1/2 of screen) across the screen
setpg - allows page to be set from 0 to 7
sety - allows Y address to be set from 0 to 64
reset - resets the LCD
enabx - performs an enable, enabling the action specified by the information on
the bus DB0-DB7 and setting of D/I pin and R/W pin.

Today I have been able to generate a few design patterns on the screen, and have been able to scroll the images upwards. I have a routine to clear memory
but I notice from image on screen that one bit is not being deleted leaving 8 lines
across the screen. I can flash whatever is on the screen on & off at whatever rate I choose. Since I am not reading the status, I have to estinmate a delay that is needed by the HD61202 on the LCD. I shortened this delay for speedier operation and I may shorten it even more.

Posted by larrykeegan at June 12, 2005 08:57 PM