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02/02/12 15:07
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#185781 - Power-On Glitch
Responding to: ???'s previous message
Neil Kurzman said that , “I can assume you have an R/C reset on the 8052?”
Thanks Neil… I’m already using it.
It can’t solve this situation… Because proses ordinary is;
1-R/C Reset
2-8051 Start up ( It’s writing ports to logic-1)
3-My program…

Richard Erlacher said that :
“Low-side high-current drivers were driven with a positive output only to provide low-going drive to relays, LED cathodes, etc. Current was most commonly limited by resistors at the high-side, and the driver sank the current. As target devices became less power-hungry, the MCU's themselves became capable of driving some of them, hence, relatively high-current-sink low-current-source drivers at the MCU pins.”

Thans Richard. I know them.
8051 I/O maximum output current is 15-20mA (approximitly) .
Look at first schema in the below link

I won’t calculate at length. But, I/O pin output current through to Base pin is approximitly 1,9mA.
However, 8051 can supprot 15-20mA. (approx. 10 times more)
Due to that reason, current don’t have to flow outside to I/O pin.

BTW, yes at first time low-active design was significat.
ULN2003 etc. chips are used. But, some problems are noticed.
Now, Hi-Active usage has started lately. UDN2981 etc..

David Prentice said that : “The solution is simple. An external pull-up or pull-down resistor… If you designed active-low, you use a pull-up. Active-high needs a pull-down.”
Thanks David…
I’ve already tried diffrent resistors between 5k and 10Ω. Anything hasn’t changed at the high value resistors. Output is not at the 10Ω.

Thanks, Kai Klaas…. Very much…

I think, I should use PIC series microcontroller for this kind of circuits….

List of 34 messages in thread
Power-On Port Status Problem      Adam Blue      01/30/12 08:42      
   Wrong idea      Per Westermark      01/30/12 08:48      
   you will not      Erik Malund      01/30/12 08:49      
   you are not the only one      Erik Malund      01/30/12 09:18      
   ATMEL be ashamed      Adam Blue      01/30/12 15:05      
      No, YOU should be ashamed...      Kai Klaas      01/30/12 16:15      
      Nonsense!        Andy Neil      01/30/12 16:46      
      PIC Does so      Neil Kurzman      01/30/12 23:08      
         Oh really??      Michael Karas      01/31/12 07:46      
            "Glitch" in the sense of kind of "setback in a plane"?      Kai Klaas      01/31/12 10:19      
   Try These Ideas        Michael Karas      01/30/12 17:21      
   "Glitch"      Adam Blue      02/01/12 13:12      
      what is not “ATMEL true”.      Erik Malund      02/01/12 13:37      
      I think you are making excuses      Erik Malund      02/01/12 13:41      
      Oh, boohoo!        Rob Klein      02/01/12 14:04      
      What a bunch of fatty sausage...      Michael Karas      02/01/12 14:59      
      "very easy problem"      Andy Neil      02/01/12 15:02      
   Power-On Glitch      Adam Blue      02/01/12 15:40      
      Nonsense - again      Andy Neil      02/01/12 16:28      
      Please explain what the "power-on glitch" is ...      Richard Erlacher      02/01/12 19:26      
      Into The Frying Pan        Michael Karas      02/01/12 20:52      
      Power-on problem...      Kai Klaas      02/02/12 05:55      
      You are still blaming the tools      Per Westermark      02/03/12 05:55      
   Design the hardware first.      David Prentice      02/02/12 07:21      
      do not Design the hardware first.      Erik Malund      02/02/12 07:30      
   Power-On Glitch      Adam Blue      02/02/12 15:07      
      that you had the worst possible reset circuit      Erik Malund      02/02/12 15:59      
      RC-reset...      Kai Klaas      02/02/12 17:20      
      Sorry, double post, don't know why...      Kai Klaas      02/02/12 17:21      
         No, you're not the only one      Richard Erlacher      02/02/12 21:12      
      Would I Hire?      Michael Karas      02/02/12 22:44      
         incidentially      Erik Malund      02/03/12 07:09      
   Power On satus Problem      Satish S Munot      02/29/12 10:16      
      echo, echo, echo      Erik Malund      02/29/12 10:30      

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