LCDInfo.com

hai iam new to this forum, and iam glad to see so many good people out there to share their knowledge.

Well i have a lcd module with built in controller(LC7981) +memory
192x128 dot matrix lcd

the microprocessor is taking too much time inorder to dump the display information to the lcd as a result of which the processors performance is degraded.

The increased time cause:
(1)i dont have direct access to sram, i have to access sram only throu' controller after passing suitable command words. (This has to be done for every 8 pixel of information) (192x128)/8 words has to sent. as i also have to take care of control signal cannot use dma


If not is their any solution to solve this problem

Are their lcd modules available in the market which allows dumping of display information directly to sram rather than throu' controller (assuming sram to be dual ported )

Perhaps the real problem lies with the code? Optimize more

hai thanks for ur response micheal,

but the actual promblem is my embedded system runs a OS so dumping data to lcd is not the only task that has to handled at a time,their are hardware interrupts like serial port interrupts, timer etc.,

My micprocessor doesnot have port pins and the lcds data pin d0 to d7 is connected to one port (byte access),
while the control lines like cs, rd , enable etc are connected to another port (byte access).
since the lcd moudle runs on lc7981( which does not contain auto write mode) i have to first pass the command word and then the data word.

for sending a single data, either be command or data the below routine must be followed expect for the change in the control value /data value
MOV AL,08H
MOV DX,DISPLAY_CONTROL
OUT DX,AL

MOV AL,BL ;//data byte in bl register
MOV DX,DISPLAY_DATA ;//port address of the display data lines
OUT DX,AL ;//place the data on the data lines of the display

MOV AL,88H
MOV DX,DISPLAY_CONTROL ;//control port address
OUT DX,AL ;//send control signals to latch the data

MOV AL,08H
MOV DX,DISPLAY_CONTROL
OUT DX,AL ;//reset the control reg port

this has to be carried out by the processor for the entire 3076=(192x128)/8 sets of data, including the cursor set , apart form creating cga display buffer, handling serial port interrupt

I want to reduce the load on the processor by taking the dumping of lcd information to lcd from the processor or atleast try to reduce the processors working time on lcd.

If nothing cant be done is there any lcd module (192x128) available in the market which could solve the problem.
Thanks
sorry for the bad english that i have

By quickly looking at the datasheet it looks to me to be like pretty much any typical LCD-controller where you set the address to be written to and then just write all the data you need and it automatically increments the address counter.

So you only send the control commands setting the address once and then just latch in all the data you need.

hai zee,
i have to first latch the command value to indicate the value to be latched next is data (pixel information), Though the addresscounter automatically by one, but have to do the above mentioned for the each pixel information i send