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Erik Malund
01/11/12 13:21
Read: 373 times
Mt Airy, Nc
USA


 
Msg Score: +1
 +1 Good Answer/Helpful
#185437 - no, you can't
Responding to: Richard Erlacher's previous message
If you can find a solid specification for exactly how long the RESET/nRESET pin on your particular MCU must be held high or low, then, with the aid of a calculator and a schmidt-trigger inverter, you can fabricate a circuit that produces a sufficiently long active-high/low pulse of appropriate voltage and stability during both power-up/power-down conditions and occasional brownouts, should they occur.

no, you can't

a) a schmitt trigger requires a minimum Vdd and thus the output is unknown at low Vdd
b) there is no way in hades a RC circuit with or without a schmitt trigger can generate a reset at power down

Erik


List of 7 messages in thread
TopicAuthorDate
AT89ISP Reset Pin Issue      Jon Wilder      01/11/12 12:02      
   If you want a positive-going RESET ...      Richard Erlacher      01/11/12 13:10      
      no, you can't        Erik Malund      01/11/12 13:21      
         You can do it, though you may not want to      Richard Erlacher      01/11/12 23:35      
   The AT89ISP will expect active-high RESET      David Prentice      01/11/12 13:11      
   Try to run the initialize target command...      Kai Klaas      01/11/12 17:13      
      By the way...      Kai Klaas      01/12/12 07:57      

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