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???
12/05/05 13:56
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 		 #104708 - Problem Solved.
Responding to: ???'s previous message
Dear Kai,

The problem solved by filtering the Vcc for comparator section. I havent been able to see the things on scope but with my 35uS comparator Inetrrupt service routine there is no problem now, I monitered atleast 2000 Zero crosses by measuring time interval in between two zero crosses and displaying this on PC using serial link the erratic zero crosses that were earlier coming one after the other in few us are now not seen at all. Thank you very much for your kind help.

Thanks & Regards,
Prahlad Purohit

List of 35 messages in thread
TopicAuthorDate
LPC922 Comparator Interrupt Problems.            01/01/70 00:00      
   Vcc?            01/01/70 00:00      
      Vcc=3.0 to 3.3 Volts.            01/01/70 00:00      
         Possible causes            01/01/70 00:00      
            Noise could come from comparator itself            01/01/70 00:00      
               Re: Noise from Ground.            01/01/70 00:00      
                  Filter            01/01/70 00:00      
                     Exactly!            01/01/70 00:00      
                  R21 is contaminated            01/01/70 00:00      
                     Hystresis is 1.7 mV            01/01/70 00:00      
                        It's 20mV!            01/01/70 00:00      
                           oops calculation error            01/01/70 00:00      
                              waaaay too small a hysteresis..            01/01/70 00:00      
                                 Not at all !            01/01/70 00:00      
                                    there are (at least) 2 ways to skin this            01/01/70 00:00      
                                       Extreme care??            01/01/70 00:00      
                                          correct, but there has been umpteen post            01/01/70 00:00      
                     Please Suggest some filtering.            01/01/70 00:00      
                        100R plus 47µF            01/01/70 00:00      
                           Re: 100E + 47uF            01/01/70 00:00      
                              Like that...            01/01/70 00:00      
                                 Red LED.            01/01/70 00:00      
                                    Every red LED should work            01/01/70 00:00      
                                       also be aware            01/01/70 00:00      
                                          At 500µA...            01/01/70 00:00      
            Noisy ground?            01/01/70 00:00      
            Re: Possible Causes.            01/01/70 00:00      
               Mains Signalling?            01/01/70 00:00      
                  Mains filtering            01/01/70 00:00      
                     mains filtering            01/01/70 00:00      
                        Very informative!            01/01/70 00:00      
   Problem Frequency.            01/01/70 00:00      
      Filtering will help!            01/01/70 00:00      
         Problem Solved.            01/01/70 00:00      
            Nice to hear!            01/01/70 00:00      

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