> The range where the display is visible rather narrow and varies
> quite a bit from module to module.  If you do not have the proper
> settings the display won't be visible.

I've salvaged a lot of LCDs, from 8x1 to 40x4, and can honestly
say I've never found one that wasn't pretty much optimum with
Vo a touch above 0V.

However, if you are new to LCDs, or a particular LCD, it is good
advice to include a contrast adjustment. As you say, the good
viewing range is quite narrow. In fact for some LCDs, tying Vo to
ground makes the off pixels dark enough that the characters can't
be seen even when the display has been initialised correctly. It's
black-on-black printing, and *that* I have been caught out with

Joe


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