U can use HC595 shift registers to drive the display. So you will need only 4 IC's. The resistors have to stay for current limitting, but you can use SMD resistors so U will have 86 holles less to drill. ;) Mircea Chiriciuc EMCO INVEST ----- Original Message ----- From: "Dennis Noordsij" To: Sent: Monday, May 27, 2002 7:42 PM Subject: [EE]: Part reducement Hi, I am making a few PCB's containing 4 7 segment LED displays, which are daisy chaised through 74HC164 shift registers, using 2 pins on a PIC to drive them all. This all works fine, but for each PCB I currently use 2 shift register IC's (for a total of 16 output pins, 4 per 7 segment display), and for each 7 segment display a 74LS249 BCD-to-7segment decoder IC, which have open collector outputs so add one resistor per segment (total of 28 + 1 dp per PCB), for which I can of course use compact housings containing several resistors in one. This adds up to 6 IC's and 29 resistors per PCB. i.e. over 150 holes to drill :) I am wondering if anyone knows a more compact version, i.e. less parts. The price of this setup is fine, but simpler is usually better. I have looked for 3 1/2 -in-one segment displays, but couldn't find any around here, so I can't rely on some obscure all-in-one unit. I can source most "regular" IC's here, so I'll build it from seperate 7 segment displays (common kathode). Any suggestions? Such as BCD convertors with more outputs, larger shift registers with enough grunt to drive the segment LED's? etc? Regards, Dennis PS - I can use an LCD, but for this particular application I prefer the big bright easy-to-read-also-from-a-distance LED displays. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body