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???
04/03/10 21:05
Modified:
  04/03/10 21:10

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#174821 - It's a highly dynamical thing...
Responding to: ???'s previous message
Rickey said:
And in something simple like statically showing a number on a 7 seg I don't see why it needs to be reset.

A microcontroller is a thing that is highly dynamically running inside. There's a clock which must start up at power-on and which only works properly after a few milliseconds. Then, there's an auxiliary potential to be generated about twice the supply voltage to allow the flash to be burned. Also, many registers and flip-lops, all the counters, PCAs, watchdog, UARTs are in a random state which must be initialized. In fact, there's nothing more important than a proper reset, one which highly reliably works at power-on, power-off and during supply voltage dips (brown-out conditions).

In conjunction with the AT89S51/52, which you probably intend to use, I usually take a MAX1232, which contains not only a reset circuitry but also a watchdog, like in this example circuit:

http://www.8052.com/forum/read/109257

and here

http://www.8052.com/forum/read/109412

Kai Klaas

List of 24 messages in thread
TopicAuthorDate
New with MCUs need a little help.            01/01/70 00:00      
   Hi            01/01/70 00:00      
      Some answers but now concerns            01/01/70 00:00      
         Normally very weak source            01/01/70 00:00      
            Can't find that detail            01/01/70 00:00      
               Not many 805x's have push-pull outputs.            01/01/70 00:00      
         Reset            01/01/70 00:00      
         SDCC            01/01/70 00:00      
   Books            01/01/70 00:00      
   Electronics            01/01/70 00:00      
   first read "the bible"            01/01/70 00:00      
      Maybe not First?            01/01/70 00:00      
         Rickey?            01/01/70 00:00      
            I am new, Just somthing I wanted to do.            01/01/70 00:00      
      Dead links            01/01/70 00:00      
         No you are right            01/01/70 00:00      
            hrm            01/01/70 00:00      
               Argh!!!            01/01/70 00:00      
               It's a highly dynamical thing...            01/01/70 00:00      
                  a reset writeup, but you don't want to read it now            01/01/70 00:00      
                     You mean this one?            01/01/70 00:00      
                        Thanks            01/01/70 00:00      
         not dead, just incorrectly copied            01/01/70 00:00      
            Thanks            01/01/70 00:00      

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