16x2 636


New member
I just obtained an LCD 16x2 kit (Crystalfontz 636). I have no idea how to put this together. Any help would be greatly appreciated. Thankz.:confused:
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CF Tech

The "636" is a "HD44780" compatible LCD. These are also commonly referred to as "parallel" or "character" LCDs.

First, please read the disclaimer here:


The schematic used is determined by the software, not the display. The most common schematic is shown below. Please determine which software you are going to use, then see what schematic it recommends.

Here is a page about 44780 based LCD's in general.

Here is a tutorial on a typical LCD parallel connection to a PC's printer port:


Then click on "LCD Display", and then "Step by Step how to build an LCD Display" (it is a framed site).

Another "Hooking up parallel LCDs" Article:


Both of these use this common schematic, less Rlimit:

We do not recommend using a potentiometer alone for the backlight. It is too easy to ruin the backlight by turning the pot too far. You should calculate the limiting resistor as described in this post to limit the maximum current (and set the maximum brightness) and then put that in series with a pot if you want to dim the backlight.

Here are some pages with some general LCD connection details: