Quirky old LCD

[Randy Day]

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...

 

[John Larkin]

On Tue, 2 Feb 2010 15:04:37 -0600, Randy Day <randy.day@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

 

[Randy Day]

In article <3qehm5hfnfg9sjcfqm8071eulkej9danm7@4ax.com>,
jjlarkin@highNOTlandTHIStechnologyPART.com says...

On Tue, 2 Feb 2010 15:04:37 -0600, Randy Day <randy.day@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.

 

[IanM]

Randy Day wrote:

In article <3qehm5hfnfg9sjcfqm8071eulkej9danm7@4ax.com>,
jjlarkin@highNOTlandTHIStechnologyPART.com says...
On Tue, 2 Feb 2010 15:04:37 -0600, Randy Day <randy.day@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:

 

[ian field]

"Randy Day" <randy.day@sasktel.netx> wrote in message
news:MPG.25d24f582b1a02e19896af@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.