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???
02/20/07 11:47
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 		 #133303 - byte programming time
Responding to: ???'s previous message
The datasheet says, byte programming time is 8us. Even if this most probably falls into the "typical" values, and even if this appears to be the net programming time and IAP adds a software overhead significantly bigger than that, it's still several orders of magnitude less than the WDT timeout (which is in the order of milliseconds with typical crystals).

Thus, IMHO it is fair to assume that it's safe to feed the dog before calling IAP without the risk of inadvertent WD reset.

OTOH, what happens if a watchdog reset would fire in the middle of statusbyte programming? If it is not programmed at all yet, the application would fire up again, so you can activate NoTouch again. And if it's programmed, NoTouch worked and the bootloader gets active right away.

Of course, using the watchdog feed in IAP would doubtlessly contribute to the feeling of security...


0.02SKK

Jan Waclawek

PS. Lynn, may we know WHY are you asking this?


List of 27 messages in thread
TopicAuthorDate
Question on "No-Touch" and watchdog            01/01/70 00:00      
   I maybe missing something too            01/01/70 00:00      
   byte programming time            01/01/70 00:00      
      the reason is            01/01/70 00:00      
         the point is somewhere else...            01/01/70 00:00      
         The reason I asked is...            01/01/70 00:00      
            Noob???            01/01/70 00:00      
               Yes, Noob            01/01/70 00:00      
                  re phil ARGH NXP IAP            01/01/70 00:00      
                     Flash Magic            01/01/70 00:00      
                        NoTouch LPC900            01/01/70 00:00      
                           correct            01/01/70 00:00      
            He can't possibly give a _solution_....            01/01/70 00:00      
               no touch for 936            01/01/70 00:00      
                  a word from the author            01/01/70 00:00      
                     ok but            01/01/70 00:00      
                        Joes 935 works, what is the question?            01/01/70 00:00      
                           backdoor & no touch            01/01/70 00:00      
                              the difference            01/01/70 00:00      
                                 It is ok            01/01/70 00:00      
   idea            01/01/70 00:00      
      you would not know about ISP, would you            01/01/70 00:00      
   if it is the 'H' chips (Rx2H and C66x) , then            01/01/70 00:00      
      Setting the Watchdog            01/01/70 00:00      
         i referred to NOT setting the watchdog during ISP            01/01/70 00:00      
         Lynn - What is your original requirement?            01/01/70 00:00      
            Original Requirement            01/01/70 00:00      

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