7 Segment LED
Martin R. Green email (remove spam text)
Correction, when I reread the original post, I realized that I had spouted
crap, sorry. The TIL311 was a single digit, 7 segment device as you
stated, but it did in fact have an on-chip BCD to 7seg decoder/latch.
As I said, I will try to find the specs on this for you.
Martin R. Green
From: MARTIN Green
Sent: Wednesday, September 10, 1997 11:01 AM
To: 'pic microcontroller discussion list'
Subject: RE: [OT] 7 Segment LED
If I remember correctly (and I might not) the TIL311 is a smart LED, with a
4 character addressable latch. I think these devices were actually 15
segment devices, allowing display of the complete ASCII set. The logic
circuits are 5V TTL. I will check at home to see if I still have info on
these useful, but way expensive devices.
CIAO - Martin R. Green
From: Jacques Vrey[SMTP:IT.NEW.ISCORLTD.CO.ZA] jvrey
Sent: Wednesday, September 10, 1997 4:30 AM
Subject: Re: [OT] 7 Segment LED
> +ve through resistor to pin and probe for cathode.
> Common cathode, gnd connected to cathode - lots of segments light up in
> (bingo) start writing down pin allocations.
> Common anode, gnd connected to anode - no segments light up. Connect +ve
> through resistor to pin and start writing down segmemnts.
> Common anode, gnd connected to segment - only one segment lights up.
> +ve to pin which lights segments and start writing down pin allocations.
> There may be some pins which are not connected, or which are bridged
> together. If you have a meter in series with the 3V supply it's easy to
That was the first thing I tried and all I managed to locate was the
This 7seg has a small chip in it that appears to do some decoding as
each segment actually consists of four individual LED's as such:
| | 14|0 0|1
| o o o o | | |
| o o | 13|0 0|2
| o o | | T |
| o o o o | 12|0 I 0|3
| o o | | L |
| o o | | 3 0|4
|o o o o o o | | 1 |
| | 10|0 1 0|5
| +---+ | | |
| |IC | | | |
| | | | | |
| +---+ | 8|0 0|7
Maybe this will shed some light on the problem.
Iscor Steel Profile Products
Tel: +27 (0)3431 48759
See also: www.piclist.com/techref/displays.htm?key=led
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