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Jan Waclawek
03/08/12 22:43
  03/08/12 22:45

Read: 568 times

#186513 - what's hobbies about
Responding to: Michael Karas's previous message
A "dedicated unlocker" could be concocted on a breadboard within perhaps a hour, if you have all the components at hand. It's just to set proper logic levels on a bunch of pins, provide +12V (possibly through a resistor - it draws only "logic" amount of current) on /EA and then a pulse on ALE. Maybe it needs some sequencing but I doubt it's more than what can be done with a simple mechanical switch. The pulse on ALE might need to be provided from a clean source, but for starter I would use a plain pushbutton. If the clock fuse is set to non-crystal you might need to provide an external oscillator, too, but then you'd need that also for ISP anyway. Yes you might fry your chip in the process, but if I understood it correctly, it was a freebie and you don't really need it.

I know that from economical point of view it is a nonsense, but we are not talking economics here, do we.

Isn't *this* what hobby is all about?


List of 7 messages in thread
AT89S8253 SerProgEn Fuse      Jon Wilder      03/07/12 18:18      
   Situation Vague      Michael Karas      03/07/12 23:38      
   fuse bits      Jan Waclawek      03/08/12 00:35      
      I have plenty of 8253's in stock...      Jon Wilder      03/08/12 08:44      
         Unless You Call a Favor      Michael Karas      03/08/12 13:53      
            what's hobbies about      Jan Waclawek      03/08/12 22:43      
               Unlocked      Jon Wilder      03/16/12 06:05      

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