Hi!
i have a small lcd display with 38 pins and no idea of the pin layout,
could you help me?
Thanks
Assuming it's just a passive LCD with no chips on it, then it's usually
quite easy by experimentation.
1) Examine closely with a magnifying glass, while holding it at
different angles to the light. You may be able to see the tracks on
the glass and where they connect.
2) Take a low voltage AC source, around 5V and 50-60Hz is good. Attach
two probes, put a resistor in series with the AC source, to limit the
current in case you short your probes, 10Kohms would be fine.
[Using DC sort of works, but is not really recommended as it
degrades the LCD in time.]
Now probe 2 pins at random. Usually two segments will turn black.
Move one probe to another pin, one segment will stay black and
the second black segment will move. Now you know the segment that
stayed black corresponds to the probe you didn't move.
Continuing like this, one can deduce all the segments. If you only
get one segment black with a pair of pins, then one of the pair is
the common to all segments (known as the "backplane").
3) Some LCDs are made for multiplexed operation and have more than one
backplane pin, this confuses things but if you think logically you
can still work it out.
Mike.
