I'm not sure this would help. Yes you could drive each segment with a higher current directly, but you would have seven times more things to MUX, so the duty cycle would now be 1 in 42 instead of 1 in 8, so the perceived brightness would drop to too low a level to be practical, without driving the LED's with 7 times more current (1120 mA), which again is too much for the PIC. Unfortunately, a catch-22. Of course, if the human eye responds more to the _peak_ intensity than the average intensity, as has been suggested in this list, then your suggestion might work, but I have not found this to be the case. The other challenge with MUX'ing all segments separately is that you would need 42 port pins, unless you used some kind of external S2P chip (or several), which kind of defeats the "PIC direct drive" theme of this thread. Finally, and this is not something I mentioned in my original post, LED's have a fairly high capacitive component, making them tend to stay on a little after the drive current is removed (I learned this when I built a IR R/C device operating at 40KHz). The faster you MUX them, the more likely you are to encounter segment bleed, for a different reason than the one I mentioned in my original post. This might not prove to be a problem, but it needs to be considered. As I stated originally, I believe Microchip's examples are highly optimistic. the only LED's I can see them working well with are those tiny "bubble" LED's with little magnifying lenses over each character. These have minuscule current requirements. CIAO - Martin R. Green elimar@bigfoot.com ---------- From: Mike Smith[SMTP:mikesmith_oz.nosp*am@relaymail.net] Sent: Tuesday, September 16, 1997 12:46 AM To: PICLIST@mitvma.mit.edu Subject: Re: Multiplexing Seven Segment Displays On 15 Sep 97 at 18:44, Martin R. Green wrote: > Ok, there's a couple of fairly simple calculations that will tell A _bunch_ of my original post snipped. > efficient or small LED's. Good coverage of led muxing. What do you think of the idea of muxing even *faster*, and driving only *one* segment at any one time, at the absolute max currents? That wouldn't violate the pin or package limits, but would increase s/w complexity. MikeS (remove the you know what before replying)