It is not a matter of age, it is matter of
"standard temp range" or "extended temp range".

Std temp range (normaly 0-70 deg) doesn't need a
negative contrast voltage.

Extended temp range (normalt from -40 and up) need
a negative contrast voltage.

Both variants are as old or modern as anything.

Regards,
Jan-Erik.




Isaac Marino Bavaresco wrote 2014-04-24 16:48:
> I remember older LCD modules that needed negative voltage at Vo pin, but
> that was in the 80's and 90's.
> For a long time now you just connect the Vo pin to GND via a trim-pot or
> a controlled current sink.
>
> Isaac
>
>
> Em 24/04/2014 11:26, Jacopo Monegato escreveu:
>> it *should* work but you need nevative voltage for lcd contrast, which i=
s about vdd-4.5V if i remember right. that's why you can connect that pin t=
o gnd if you power the controller with 5 volts
>>
>>> Subject: [PIC] Use HD44780A display controller with 3.3 volt PICs?
>>> From: larry.bradley@ncf.ca
>>> To: piclist@mit.edu
>>> Date: Thu, 24 Apr 2014 10:11:08 -0400
>>>
>>> I have a collection of LCD displays, all of which use the HD44780A
>>> controller. I'd like to use these with a PIC24H. From the data sheet, i=
t
>>> appears that the  chip should be happy with the 3.3 volt O/P of a
>>> PIC24H, since the input pins need a min of 2.2 volts.
>>>
>>> Has anyone tried this?
>>> --
>>> Larry Bradley
>>> Orleans (Ottawa) Canada
>>>
>>> --
>>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
>>> View/change your membership options at
>>> http://mailman.mit.edu/mailman/listinfo/piclist
>>   		 	   	=09
>
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