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???
02/02/06 13:54
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 		 #108972 - Read between the lines...
Responding to: ???'s previous message
I'm really bummed out about the AT89S8253, as the AT89S8252 was a real solid performer. I think this is a step back for Atmel, and I'm hoping that they change the silicon back to a 30pF oscillator loading and fix the errata problems.

Trevor, you haven't read the datasheet of AT89S8253 properly. You must read between the lines. Atmels tells you not to use a quartz at higher frequencies. Why? If you have a look at the picture showing amplitude of signal versus frequency, then you will notice that amplitude at higher frequencies is a bit to little to work reliably, especially if you take manufacturing tolerances into account.
In this oscillator there's a bug, definitely, and I would highly recommend you to use an external oscillator, if you want a clock frequency beyond 20MHz.

Kai

List of 27 messages in thread
TopicAuthorDate
AT89S8253 Clock Oscillator Problem            01/01/70 00:00      
   Crazy value            01/01/70 00:00      
      RE:Crazy value - AT89S8252 Osc Loading            01/01/70 00:00      
         oscillates ?            01/01/70 00:00      
            Oscillator Comparison            01/01/70 00:00      
               PRE tags            01/01/70 00:00      
                  Table explained            01/01/70 00:00      
                  External Oscillator            01/01/70 00:00      
   if "around 7" is 8, then I would say you            01/01/70 00:00      
      I'd say so, but...            01/01/70 00:00      
         3rd overtone crystals are "real fun"            01/01/70 00:00      
      3rd overtone            01/01/70 00:00      
         please elaborate            01/01/70 00:00      
            not a string            01/01/70 00:00      
            Tuning the marimba...            01/01/70 00:00      
               waaay beyond the subject rel to above            01/01/70 00:00      
                  Evelyn Glennie            01/01/70 00:00      
                     thanks, Steve            01/01/70 00:00      
         Excerpts from a Maxim appnote            01/01/70 00:00      
      24 MHz Fundamental Mode            01/01/70 00:00      
         If history repeats itself, you are going            01/01/70 00:00      
            Come on...            01/01/70 00:00      
         Read between the lines...            01/01/70 00:00      
            Thanks Kai - AT89S8253, LP4052            01/01/70 00:00      
               to Trevor            01/01/70 00:00      
         G8DVN            01/01/70 00:00      
            OT:Get that HF Ticket!            01/01/70 00:00      

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