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???
07/10/03 02:11
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 		 #50388 - RE: Short Timing delays- Dave
Responding to: ???'s previous message
Dear Dave,

Thanks for your time.

But I think the solutions of introducing a Delay Line or using a chip like C8051F020 which has a SFR for External Memory Timing control WILL solve the problem.

Let me explain the actual timings of a typical 80c51 from Philips with 12Mhz clock and 12clock cycles:

External Memory Read :

200 nanoseconds after #ALE goes low, #RD goes low and remains low for 399.8 nanoseconds.

Immediatley after #RD goes low, P0 is ready to take data in for 399.8 nanapseconds and address valid to data valid is 859.5 nanoseconds.

What I am trying to do is to play around within the time frames that have been indicated in bold above and give the external chip the additional time to prepare its data.

And your concern was :
"could mean that the RD pulse will have gone high internally, and therfore latched the data bus contents, long before the data is valid. "

The above cannot happen, if I do, what I have explained above.

Raghu
I think this

List of 56 messages in thread
TopicAuthorDate
Short Timing delays            01/01/70 00:00      
   RE: Short Timing delays            01/01/70 00:00      
      Applications of 80C320            01/01/70 00:00      
         RE: Applications of 80C320            01/01/70 00:00      
   RE: Short Timing delays            01/01/70 00:00      
      RE: Short Timing delays            01/01/70 00:00      
         RE: Short Timing delays            01/01/70 00:00      
            RE: Short Timing delays            01/01/70 00:00      
               RE: Short Timing delays            01/01/70 00:00      
                  RE: Short Timing delays            01/01/70 00:00      
                     RE: Short Timing delays            01/01/70 00:00      
                        RE: Short Timing delays            01/01/70 00:00      
                           RE: Short Timing delays            01/01/70 00:00      
                              RE: Short Timing delays            01/01/70 00:00      
                                 RE: Short Timing delays            01/01/70 00:00      
                                    RE: Short Timing delays            01/01/70 00:00      
                              RE: Short Timing delays            01/01/70 00:00      
                                 RE: Short Timing delays            01/01/70 00:00      
                                    RE: Another interpretation            01/01/70 00:00      
      RE: Short Timing delays            01/01/70 00:00      
         Inverter string delay            01/01/70 00:00      
            RE: Inverter string delay            01/01/70 00:00      
               RE: Inverter string delay            01/01/70 00:00      
   RE: Short Timing delays            01/01/70 00:00      
      RE: Short Timing delays            01/01/70 00:00      
         RE: Short Timing delays            01/01/70 00:00      
            RE: Short Timing delays            01/01/70 00:00      
               RE: Short Timing delays            01/01/70 00:00      
                  RE: Short Timing delays            01/01/70 00:00      
                     RE: Short Timing delays            01/01/70 00:00      
                     RE: Short Timing delays            01/01/70 00:00      
   RE: Short Timing delays - DeMorganite            01/01/70 00:00      
   RE: Short Timing delays            01/01/70 00:00      
      RE: Short Timing delays            01/01/70 00:00      
         RE: Short Timing delays            01/01/70 00:00      
   RE: Short Timing delays            01/01/70 00:00      
      RE: Short Timing delays            01/01/70 00:00      
         RE: Short Timing delays            01/01/70 00:00      
            RE: Short Timing delays            01/01/70 00:00      
   RE: Short Timing delays            01/01/70 00:00      
      RE: Short Timing delays            01/01/70 00:00      
         RE: Short Timing delays            01/01/70 00:00      
            RE: Short Timing delays            01/01/70 00:00      
         Bubbles            01/01/70 00:00      
   RE: Short Timing delays            01/01/70 00:00      
      RE: Short Timing delays- Erik            01/01/70 00:00      
         RE: Short Timing delays- Erik            01/01/70 00:00      
            RE: Short Timing delays- Abhishek            01/01/70 00:00      
               RE: Short Timing delays- Abhishek            01/01/70 00:00      
   RE: Short Timing delays            01/01/70 00:00      
      RE: Short Timing delays            01/01/70 00:00      
   RE: Short Timing delays            01/01/70 00:00      
      RE: Short Timing delays            01/01/70 00:00      
   RE: Short Timing delays            01/01/70 00:00      
      RE: Short Timing delays- Dave            01/01/70 00:00      
      RE: Short Timing delays            01/01/70 00:00      

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