I've got an old 16x2 character LCD, no make or 
model number visible. It uses an SED1278F0A
and a KS0065. I can get it to display 
characters, just not the right ones. 

For instance, if I instruct it to display 
'0123456789ABCDEF' on line 1, it displays 
'45674567<=EFGDEF'.

If I send it the word 'Processor', it does a 
kind of ROT-4 conversion on it, displaying 
character 'n+4' instead of 'n'.

Also, when I display on line 2, the characters
start printing at position 4.

Did I mention I'm starting to hate the number 4? :)

Has anyone seen this behavior before? I'd like 
to use this display in a project, but it's got 
me scratching my head...

On Tue, 2 Feb 2010 15:04:37 -0600, Randy Day <r...@sasktel.netx>
wrote:

>I've got an old 16x2 character LCD, no make or 
>model number visible. It uses an SED1278F0A
>and a KS0065. I can get it to display 
>characters, just not the right ones. 
>
>For instance, if I instruct it to display 
>'0123456789ABCDEF' on line 1, it displays 
>'45674567<=EFGDEF'.
>
>If I send it the word 'Processor', it does a 
>kind of ROT-4 conversion on it, displaying 
>character 'n+4' instead of 'n'.
>
>Also, when I display on line 2, the characters
>start printing at position 4.
>
>Did I mention I'm starting to hate the number 4? :)
>
>Has anyone seen this behavior before? I'd like 
>to use this display in a project, but it's got 
>me scratching my head...

Sure sounds like D2 (the '4' bit) is stuck high.

John

In article <3...@4ax.com>, 
j...@highNOTlandTHIStechnologyPART.com says...
> On Tue, 2 Feb 2010 15:04:37 -0600, Randy Day <r...@sasktel.netx>
> wrote:
> 
> >I've got an old 16x2 character LCD, no make or 
> >model number visible. It uses an SED1278F0A
> >and a KS0065. I can get it to display 
> >characters, just not the right ones. 
> >
> >For instance, if I instruct it to display 
> >'0123456789ABCDEF' on line 1, it displays 
> >'45674567<=EFGDEF'.
> >
> >If I send it the word 'Processor', it does a 
> >kind of ROT-4 conversion on it, displaying 
> >character 'n+4' instead of 'n'.
> >
> >Also, when I display on line 2, the characters
> >start printing at position 4.
> >
> >Did I mention I'm starting to hate the number 4? :)
> >
> >Has anyone seen this behavior before? I'd like 
> >to use this display in a project, but it's got 
> >me scratching my head...
> 
> Sure sounds like D2 (the '4' bit) is stuck high.

I wondered about that, and checked the signal 
out of the micro, but I suppose it could be 
internal. That would suck.

Maybe it's just a loose joint; I'll have to 
take a magnifier to the PCB.

Thanks.

Randy Day wrote:
> In article <3...@4ax.com>, 
> j...@highNOTlandTHIStechnologyPART.com says...
>> On Tue, 2 Feb 2010 15:04:37 -0600, Randy Day <r...@sasktel.netx>
>> wrote:
>>
>>> I've got an old 16x2 character LCD, no make or 
>>> model number visible. It uses an SED1278F0A
>>> and a KS0065. I can get it to display 
>>> characters, just not the right ones. 
>>>
>>> For instance, if I instruct it to display 
>>> '0123456789ABCDEF' on line 1, it displays 
>>> '45674567<=EFGDEF'.
>>>
>>> If I send it the word 'Processor', it does a 
>>> kind of ROT-4 conversion on it, displaying 
>>> character 'n+4' instead of 'n'.
>>>
>>> Also, when I display on line 2, the characters
>>> start printing at position 4.
>>>
>>> Did I mention I'm starting to hate the number 4? :)
>>>
>>> Has anyone seen this behavior before? I'd like 
>>> to use this display in a project, but it's got 
>>> me scratching my head...
>> Sure sounds like D2 (the '4' bit) is stuck high.
> 
> I wondered about that, and checked the signal 
> out of the micro, but I suppose it could be 
> internal. That would suck.
> 
> Maybe it's just a loose joint; I'll have to 
> take a magnifier to the PCB.
> 
> Thanks.

How confident are you in your signal timings? Allow a bit more setup and 
hold time, a wider strobe pulse and more 'busy' time and see if it 
magically starts working ;-)


Also, try running it in 4 bit mode. That uses D7-D4 so a faulty D2 input 
should be ignored.  OTOH it could be an internal fault in the controller 
IC.
-- 
Ian Malcolm.   London, ENGLAND.  (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL:

"Randy Day" <r...@sasktel.netx> wrote in message 
news:M...@news.sasktel.net...
> I've got an old 16x2 character LCD, no make or
> model number visible. It uses an SED1278F0A
> and a KS0065. I can get it to display
> characters, just not the right ones.
>
> For instance, if I instruct it to display
> '0123456789ABCDEF' on line 1, it displays
> '45674567<=EFGDEF'.
>
> If I send it the word 'Processor', it does a
> kind of ROT-4 conversion on it, displaying
> character 'n+4' instead of 'n'.
>
> Also, when I display on line 2, the characters
> start printing at position 4.
>
> Did I mention I'm starting to hate the number 4? :)
>
> Has anyone seen this behavior before? I'd like
> to use this display in a project, but it's got
> me scratching my head...

Look out for scrap DAB radios - the 2 that I've opened so far both had 16x2 
LCD modules that had type numbers that were easy to find data sheets for.