4x40 LCD control problem

[NL2TTL]

I have a 4x40 LCD display with two enable signals.

I like to control this display with 4 bit data transfer,
when 1 made a program for just a 4x20 lcd display it works fine but i can't get any signal on a 4x40 LCD display.

Does sombody have a PICbasic sample program (with schematic (no must)) to control a 4x40 display?

[mister_e]

what about if you tie to ground the 2nd ENABLE line? In this case do you have at least few characters?

Which display are you using?

[NL2TTL]

that won't work i'm using a YMS404-01 display

[Ingvar]

Perhaps this could be useful?

http://www.picbasic.co.uk/forum/showthread.php?s=&threadid=631

[NavMicroSystems]

NL2TTL,

the LCD should work on Line 1 and Line 2 if you connect only E1 to the PIC and tie E2 to GND.

for a quick test you could also connect E2 to E1, Line 3 will than be the same as Line 1 and Line 4 the same as Line 2.

On the link INGVAR has already posted you'll find an example of how to toggle between the two controllers using only one additional pin on the PIC.

IF the LCD is displaying nothing at all I guess VEE is not set correctly.

Attached is the Datasheet of the YMS404-01

Regards

Ralph

[NL2TTL]

thank you very much, only the problem is that i've already tried that.

So i have to do more tests when it's working i will post the complete schematic include the source

[mister_e]

may try a long delay time at the begining... some need close to 2 seconds for initializing correctly(as i heard, not those i currently work with).

Some define may be include/try too

DEFINE LCD_COMMANDUS

and

DEFINE LCD_DATAUS

Contrast pin may be connected to a trim pot for testing. Memory allocation should be different too.

let us know

regards

[NL2TTL]

Oke it works.

here is the code