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???
04/18/04 03:33
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#68709 - RE: 89C51RD2
Responding to: ???'s previous message
* How far is your crystal & capacitors from the MCU pins ? If they are physically more than 5-10mm ( a very rough indication ) you could have trouble. This is more a problem in wire wrapped bread board set ups.

* 33pf capacitors are just fine. 330pf is way too large.

* As already advised you better probe the ALE pin and don't expect 11.0592 MHz there ? Why ? Find out from Bible. And if you are probing the XTAL pins, ensure you probe the XTAL2 pin which is the output. Most times if you try to probe XTAL1 which is the input, you can screw up the oscillations.

* If all are OK as above, then the MCU must start oscillating. Else try changing the Crystal and then
MCU in that order.

* And when it does start oscillating first go and buy a Reset controller like DS1232 for the MCU. With a simple RC reset you will end up frustrated trying to get the 89c51rd2 do what you want and most probably end up posting here again with more problems.

Raghu



List of 7 messages in thread
TopicAuthorDate
89C51RD2            01/01/70 00:00      
   RE: 89C51RD2            01/01/70 00:00      
   RE: 89C51RD2            01/01/70 00:00      
      RE: 89C51RD2            01/01/70 00:00      
   RE: 89C51RD2            01/01/70 00:00      
      RE: 89C51RD2            01/01/70 00:00      
   RE: 89C51RD2            01/01/70 00:00      

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