Pretty much what I was thinking. You could probably output all combinations (0 thru 255) one at a time and see what the result is for each of these. If this is really the problem, you should be able to see a pattern for the combinations that fail. Cheers, -Neil. ----- Original Message ----- From: "Spehro Pefhany" To: Sent: Sunday, March 10, 2002 11:47 AM Subject: Re: [PIC]: 16F877 PORTD Can't run 8 LEDs simultaneously > At 04:59 PM 3/10/02 +0200, you wrote: > >Hi! Another strange behaviour.... > > > >I have connected 8 leds in series with 8 1K resistors respectively to PORTD, > >the LEDs light at logic "1". > > > >RD0-------|>|---/\/\/\/\------GND > >.... LED 1K > >RD7-------|>|---/\/\/\/\------GND > > > >If you light each LED alone its OK but if you try to light more than 4 the > >LEDs, RD0 and RD4 do not light even though that 5V are applied to the LEDs. > >The voltage between the particular LED leads is 0.8V > > A long shot perhaps, but if there was a short between a couple of adjacent > LED cathodes AND one LED was much lower Vf than the next one (say RD0 is > green and RD1 is red) then it would behave exactly as you describe. > > Best regards, > > Spehro Pefhany --"it's the network..." "The Journey is the reward" > speff@interlog.com Info for manufacturers: http://www.trexon.com > Embedded software/hardware/analog Info for designers: http://www.speff.com > 9/11 United we Stand > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.