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 elimar@bigfoot.com ---------- 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 elimar@bigfoot.com ---------- From: Jacques Vrey[SMTP:jvrey@IT.NEW.ISCORLTD.CO.ZA] Sent: Wednesday, September 10, 1997 4:30 AM To: PICLIST@mitvma.mit.edu Subject: Re: [OT] 7 Segment LED > > Hi, > > Sorry I don't have a diagram for you, but I have a suggestion. > > Have you tried putting one of them in a breadboard, and using a 3V supply > and a 200R resistor to check out the pins. Connect a random pin to ground > then connect each pin in turn through the resistor to +3V. > > These are the possible outcomes. > > Common cathode, gnd not connected to cathode - no segments light up. Connect > +ve through resistor to pin and probe for cathode. > > Common cathode, gnd connected to cathode - lots of segments light up in turn > (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. Connect > +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 see > which ones these are. > > Hope this is some help, > > Keith. > ------------------------------------------------------------ > Keith Dowsett "Variables won't; constants aren't." > > E-mail: kdowsett@rpms.ac.uk or kdowsett@geocities.com > > WWW: http://kd.rpms.ac.uk/index.htm > http://www.geocities.com/CapeCanaveral/Lab/8979 > > Hi there..again In response.. That was the first thing I tried and all I managed to locate was the dp's. 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. Thanks anyway. Regards Jacques Vrey Iscor Steel Profile Products Newcastle South Africa Tel: +27 (0)3431 48759 jvrey@it.new.iscorltd.co.za