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???
04/23/10 03:11
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#175302 - That the most exhaustive reply i got so far !
Responding to: ???'s previous message
After such an exhaustive, informative and descriptive answer you definitely need to open a bottle of beer and that's on me!

Thanks a million Stefan !

you have shown full steps on how to do the job with timers,and managing with only one phase ZCD pulses.

In our country, the power supply is very erratic and the mains freq. and Voltage are fluctuating with load conditions. In summers, we have power cuts/grid failures. Many people here have back up power supplies like Inverters and Generators. until recently most of the inverters owned by the people are Squarewave type or modified sine wave type. Pure sine wave inverters have come into market just 2 years back.

My design has to survive the freq & Voltage Fluctuations in these inverters.

so the idea of loading precalculated half period value into the TR is not a failsafe option.

i am working on 1Meg ZCD scheme to convert the square Wave on the i/o pin to continuous train of pulses for both phases of Zero crossings.

My idea is to use a Bridge infront of 1Meg resistor and use one more 1Meg resistor from i/o pin to GND, this results in positive falling pulses at the i/o pin at intervals of 10ms ( @ 50Hz freq)

i've simulated the above set up on Proteus, and will post the pics of the testing.

once again, thanks for sharing your thoughts and help.

Thanks Erik, can you explain me how to use a Zener to accomplish the job, and Zeners are dirt cheap here.

Regards,

Arun

List of 86 messages in thread
TopicAuthorDate
External Interrupt on both Falling edge & rising edge            01/01/70 00:00      
   ABORT!, ABORT!, ABORT!            01/01/70 00:00      
      Better circuits exists            01/01/70 00:00      
      one more            01/01/70 00:00      
   DANGER!! Don't Try This At Home!            01/01/70 00:00      
      Its not just Atmel            01/01/70 00:00      
   interrupts on both edges            01/01/70 00:00      
      Thank you All            01/01/70 00:00      
         Read about external Gate for Timer            01/01/70 00:00      
            gate for timer            01/01/70 00:00      
               Jan, will you Shhhhh!!!            01/01/70 00:00      
               Great Idea !            01/01/70 00:00      
                  But i've used up INT0 and INT1 pins            01/01/70 00:00      
                     int0 is gate for timer0            01/01/70 00:00      
                     T1(T0) pin is not use here            01/01/70 00:00      
                        so only one Ext.int pin will do            01/01/70 00:00      
                           i think so            01/01/70 00:00      
                              I haven't tried it yet            01/01/70 00:00      
                                 is a Zener that costly?            01/01/70 00:00      
                                 so try something safely            01/01/70 00:00      
                                    That the most exhaustive reply i got so far !            01/01/70 00:00      
                                       You are wellcome            01/01/70 00:00      
                                          Here's what i have done            01/01/70 00:00      
                                             simulation is partial            01/01/70 00:00      
                                                I'll try writing a sample code            01/01/70 00:00      
                                                   Dimmer            01/01/70 00:00      
                                                      its a dimmer for commercial sale            01/01/70 00:00      
                                                         Dimmer            01/01/70 00:00      
   Its in my Profile            01/01/70 00:00      
      is 8051/2 I/O similar to Zilog Z8            01/01/70 00:00      
         Cease and Desist            01/01/70 00:00      
         It's DANGEROUS - It's not about the IOs!!            01/01/70 00:00      
         Either you are NOT listening...or you don't want to listen            01/01/70 00:00      
            It's worse than that!            01/01/70 00:00      
               Its like openning Pandora's box            01/01/70 00:00      
                  chip A != chip B != chip C            01/01/70 00:00      
                  Consider these points...            01/01/70 00:00      
                     not a newbie to electronics            01/01/70 00:00      
                        What results do you really get from an experiment?            01/01/70 00:00      
                        Reply to Arun Kumar V            01/01/70 00:00      
                  what if the result is death?            01/01/70 00:00      
                     very positive opinion            01/01/70 00:00      
                     Thanks for the pointer            01/01/70 00:00      
   A generic approach to dual edge detection            01/01/70 00:00      
      Here is the method I have been using...            01/01/70 00:00      
      Oh Noes!!!!!!            01/01/70 00:00      
      4 -> 10 nsec Pulse Does Not Work for MCU            01/01/70 00:00      
         No additional logic gates            01/01/70 00:00      
         Modifying design            01/01/70 00:00      
            Yeah But...            01/01/70 00:00      
               If you say so            01/01/70 00:00      
                  Poppycock            01/01/70 00:00      
   Why you should not do this...            01/01/70 00:00      
      Galvanic isolation            01/01/70 00:00      
         Can't we use single AC optocoupler            01/01/70 00:00      
            not 1,8V            01/01/70 00:00      
            can be wrong circuit below            01/01/70 00:00      
               Critical again...            01/01/70 00:00      
                  varistor?            01/01/70 00:00      
                     Yes, but...            01/01/70 00:00      
            You can do a lot of things...            01/01/70 00:00      
               25V is too coarse            01/01/70 00:00      
                  use tha appnote I gave you the link to            01/01/70 00:00      
                  25V is not bad            01/01/70 00:00      
                     You still don't know what my product is?            01/01/70 00:00      
                        sorry            01/01/70 00:00      
                           Its O.K - this thread has crossed 65 replies            01/01/70 00:00      
                              npn            01/01/70 00:00      
                        no, I do not know what your product is            01/01/70 00:00      
                           Answers            01/01/70 00:00      
                              OK, then            01/01/70 00:00      
                                 No headphones            01/01/70 00:00      
                  Then take a better opto!            01/01/70 00:00      
                     he wants to build a Yogo, not a Mercedes            01/01/70 00:00      
                        which makes the lamp flicker when the fridge turns-off            01/01/70 00:00      
                           it (probably) does that anyhow            01/01/70 00:00      
                              No body wants to buy a Mercedez            01/01/70 00:00      
                                 What do you expect??            01/01/70 00:00      
                                    What is there to be ashamed of ?            01/01/70 00:00      
                                       Thread began with ....            01/01/70 00:00      
                                          Dead Horse is Alive and Kicking            01/01/70 00:00      
                                             obviously a comparator is a better solution            01/01/70 00:00      
                                                Oh My God...you having sleepless nights???            01/01/70 00:00      
                                             Then share it with us...            01/01/70 00:00      
                                             to Arun PLEASE get ...            01/01/70 00:00      
                                 what did you expect            01/01/70 00:00      

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