I need some help with wiring an LCD

lstrunk · 04-30-2001, 06:46 AM

I am probably recieving my 4x40 LCD today,
aNd I don't know how to wire it.

could someone please tell me how to put in the potentiometers? Does the pin on the opposites side of the other 2 get plugged into the line that goes to the center of the Squiggly mark thing?
And, If I am using this LCD with MPXF, instead of Mpxplay, is there a different way you have to wire it?
Would anybody be really nice and give me a step by step directions for doing it, as I am just confused.

Also, when I put this LCD in the front of my car, what can I use to extend it? Is it ok to use a regular printer cable, or does all the pins not go straight through on it?
Thanks alot

mikep56 · 05-01-2001, 12:52 PM

Hi Istrunk,
1) The potentiometers (pots for short) have 3 pins. The 2 outside pins are the ends of the pot, and the pin in the middle os the wiper. One of the outside pins on each pot goes to ground, the wiper of the 100 also goes to ground , and the remaining pin of the 100 goes to pin 16 of the LCD. This controls the brightness of the backlight. The wiper of the 10K goes to pin 3 of the LCD, for the contrast, and the remaining pin of the 10K goes to +5V. The wiring diagram appears correct.

2)MPXF has a file called MPXFLCD.CFG. In the section labeled [LCD Settings], change the lines for LCD=,LCDLines=, and LCDLength= to

LCD=LPTLCD
LCDLines=4
LCDLength=40

Also in MPXPLAY.INI you need to make sure this line reads:

LCDlines =0 ;modify this to enable LCD (1 or 2)

This prevents MPXPLAY from displaying. If the LCD is enabled in both MPXF and MPXPLAY, it will not work correctly.

3) You should be able to use a parallel port extension cable.

Good Luck

Mike

Raas · 05-02-2001, 04:01 AM

I think that when you've a 4x40 than the schematic provided by you won't work. This schematic is only designed to use only 1 HD44780 controller which are (is) on the lcd-screens.

As your 4x40 is having 2 of these controllers you need a different schematic and i think this is the one... slightly different than the one provided by you.
But this one has 2 more pins to connect to (as needed for the second controller)

Hope this helps you out.

Greetz