Hitachi, HD44780 standard

[Nikolai]

Hi!

just wondering if there is a simple way of finding out if a lcd complies with the Hitachi standard. It usualy does not say "this lcd coplies with the HD4478 standard", so I want to know if there is a pin asigment to look for , or another name or such.

Thank you

Nikolai

[moebius]

HD44780 compatible LCD controllers:

[table]

[tr][td]Controller:   [/td][td]Manufacturer:[/td][/tr]

[tr][td]HD44780   [/td][td]Hitachi[/td][/tr]

[tr][td]KS0066   [/td][td]Samsung[/td][/tr]

[tr][td]KS0076   [/td][td]Samsung[/td][/tr]

[tr][td]KS0070   [/td][td]Samsung[/td][/tr]

[tr][td]S6A0069   [/td][td]Samsung[/td][/tr]

[tr][td]LC7985NA   [/td][td]Sanyo[/td][/tr]

[tr][td]SED1278   [/td][td]Epson[/td][/tr]

[tr][td]NT3881D   [/td][td]Novatek[/td][/tr]

[tr][td]SPLC780   [/td][td]Sunplus[/td][/tr]

[tr][td]MSM6222   [/td][td]OKI[/td][/tr]

[tr][td]NJU6408B   [/td][td]NJR[/td][/tr]

[tr][td]NJU6468   [/td][td]NJR[/td][/tr]

[tr][td]NJU6470   [/td][td]NJR[/td][/tr]

[tr][td][/td][td][/td][/tr]

[tr][td]Possibly:   [/td][td][/td][/tr]

[tr][td]UM3881B   [/td][td]UMC[/td][/tr]

[tr][td]T7934   [/td][td]Toshiba[/td][/tr]

[/table]

If your LCD has one of these chips, there are good changes to get it work. These chips have similar instruction set, data bus and timings are like original HD44780 (or faster, which shouldn't matter)

BUT this only means that controller chip is compatible with driver designed to HD44780  8)

It's simply easier to get a display that has datasheet available.

Common problems, if it isn't your soldering:

First: There is no common standard for display connector - You should get your LCDs datasheet to see, what the pinout is.

Second: Your display may need negative contrast voltage. (Watch out for V_ee pin.)

(check post by Smash: http://www.midibox.org/cgi-bin/yabb/YaBB.cgi?board=troubleshooting;action=display;num=1099022402)

Third: Backlight not working? Maybe it's Electroluminescent (EL) type.

And it's also good to know, that at least HD44780 displays can be initially programmed to different character sets - maybe your dirt cheap surplus display just talks greek to you ;D

Bye, Moebius

(Sources:

http://www.idwusa.com/frameset.htm?products/catalog/ModuleTypes/CharacterType/Specifications/DotCharacterPatterns.htm&1

NJR part cross reference

ect.)

[Nikolai]

Thank you for your fantastic reply!

I'll see what my electronics-shop can come up with and compare the data-sheets.

This info surly must be interesting for others.

all best

Nikolai