Interfacing a graphical lcd to my computer

[ashlol74]

Hi,
I would like to connect my graphical lcd JMK140A 128 x 64 with a novatek NT7502 controller (I m not really sure but it is normally equivalent to the NJU6676) to the parallel port of my computer because i think it is the easiest way to display a picture onto that screen. I also found this diagram
www.viperlair.com/images/articles/archive/mods/lcd/6.jpg
from this article
www.viperlair.com/articles/archive/mods/lcd.shtml
but it is incomplete as i have V1 to V5 to connect and CAP1+, 1-, 2+, 2- and 3+. From what i have understand the datasheet it depends on the mode of operation of the lcd but i don't know witch one it is.
So can anyone help me to complete the connection between the lcd and the computer and then can i use LCDinfo or powerLCD on my computer to display a picture on it ?
Thanks a lot fo helping me.

 

[ashlol74]

Plz if someone can help it would be really helpfull
thanks

 

[Sigma|Six]

Hmm...very similar to Sitronix Driver...

Well, I have some experience on Sitronix Dot Matrix Display.

First I am not sure if you have enough digital control on parallel port for this applications.
you have to control D0 to D7, A0, CS0, CS1 and preferablely /WR. you will have to switch between data mode/ command mode using A0 quite frequently or during the initilization of the LCD.

Second, if you do have enough digital line to control this thing, you won't have enough bit rate to make the display appear seamlessly as parallel port transfer rate is way too slow.

I would suggest that you come out with a uC board to interface with the LCD.

you can use PC's serial port to talk to uC board's serial port for to store the image you want to display on the uC board's RAM/memory. Then clock out the image data to LCD driver.

V1 to V5 are bias voltages for the LCD which will control you LCD's contrast, using a uC interface you should be able to control the DAC of the uC to adjust the contrast of the LCD according to your applications. or else you can always hardwire the these line so it will have a fix constrast. Or you can utilize the IRS line to select internal voltage reference for the contrast purpose.

For the CAPx+ nad CAPx-, simply connect these line to some capacitors 10uF/1uF to it, that's meant to stablize the DC to DC circuitry inside the chip.

 

[ashlol74]

Thanks for your reply,
In case i just want to write to the LCD can i put
RD (E) -> high
WR(R/W) -> low
/RES -> to a switch
/CS1 -> low
so i have only A0 and D0 to D7 to connect to the parallel port, or do i also have to use a µC as you said for this purpose (display a picture)

I saw that in the nt7502 datasheet IRS is mentionned but is not output to the connector so it must have been hard wired to low because of V1 to V5.
Is that true?

thanks again for helping me and sorry for the stupid question but i'm a real newbie in LCD.

 

[ashlol74]

is there anyone who can give me a hand plz ?
thanks again