How to connect 2nd LCD on OC USBLCD

[hollik]

Hello all,

After reading through the manual, and several forums, I am still puzzled.
I have bought 4 hd44780 compliant lcd displays and the opencockpits USBLCD card.

Now I can see how you connect the first LCD, pretty straight-forward.
However, how about a second LCD? Do they go in the same pins as the first (seems weird?), or do they go in different pins?

I have not found any information of how to connect the next lcd's.

Thank you for your help

UPDATE:

I have found it in the manual after all,

This diagram show the wiring for the display 0, to connect the displays 1, 2 y 3, we will repeat the wiring with only
one exception, the “E” connection from LCD that will be changed for the pins numbers 30, 27 y 28 respectively from
the 40 pins connector, as we can see in the above table of wiring.

Only thing that I want to know now, do I need to connect the pots, or are they just extra?

[hyamesto]

Read the page 5 of the User manual.
All connected in parallel, except pin 6 of every display.

Follow the table:

LCD 1 - pin 6 to pin 29 of card
LCD 2 - pin 6 to pin 30 of card
LCD 3 - pin 6 to pin 27 of card
LCD 4 - pin 6 to pin 28 of card

[hollik]

Thank you hyamesto, I just found out. Only thing that I am still wondering about, wouldn't the displays work without the potentiometers?

[hyamesto]

The potentiometers control the contrast (pin 3 of display) and light intensity of the display (pin 15 and 16 if the display has backlight).
You need to control contrast, due to differences in manufacturing the displays, and position of your point of view.
You can use resitores fixed, but not recommended.
Best use resistors presets.