Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
08/11/07 04:22
Read: times


 		 #143083 - No, is not. Look at INTEL's original C51 manual!
Responding to: ???'s previous message
Richard said:
I completely disagree with your interpretation of this statement as saying, simply, that the time constant of a 10 uF cap pulled down by 8K2 is enough. I believe that it says more than that, namely that, first and foremost, you must provide a Vcc rise time of < 1 ms, at the end of which time you must have reached and settled at a "legal" level for Vcc.

I'm afraid you're wrong. The original "bible" by INTEL, which you will find here

http://download.intel.com/design/MC...238302.pdf

tells a more detailed story:






Note, what they state: "On power up, Vcc should rise within approximately 10msec."

This very lax "demand" sounds more like a recommendation than a rigid rule. It simply reflects the fact, that most tiny (and by this weak) mains transformers have no chance to charge up the storage cap in front of 7805 much faster anyway.

Kai

List of 29 messages in thread
TopicAuthorDate
reset supervisors            01/01/70 00:00      
   two purposes of the IC (at least)            01/01/70 00:00      
      Unfortunately, they seem to fail at one of them            01/01/70 00:00      
         you are talking about the RC resets, I assume            01/01/70 00:00      
            No, I'm referring to the DS and Max 1232            01/01/70 00:00      
               and what            01/01/70 00:00      
                  It's just not that simple ...            01/01/70 00:00      
                     I am getting tired            01/01/70 00:00      
                        Reset chips do work properly and prevent damage!            01/01/70 00:00      
                           I never doubted that, Kai            01/01/70 00:00      
                              can you please be more precise...            01/01/70 00:00      
                                 Yes            01/01/70 00:00      
                              It is a black box and you will never find out...            01/01/70 00:00      
                                 It\'s the power supply, and probably not the reset.            01/01/70 00:00      
                                    That's not what the bible states...            01/01/70 00:00      
                                       Isn't that the same thing with different syntax?            01/01/70 00:00      
                                          No, is not. Look at INTEL's original C51 manual!            01/01/70 00:00      
                                             Vcc rise time            01/01/70 00:00      
                                                It can, I believe, be done simply.            01/01/70 00:00      
                                             Brown-out Bug Chasing            01/01/70 00:00      
                                                Seems reasonable            01/01/70 00:00      
                                             There's been nothing specific enough to test.            01/01/70 00:00      
                                                Some hints            01/01/70 00:00      
                                                   it's a thorny problem            01/01/70 00:00      
                                                      Add a monoflop            01/01/70 00:00      
                                                         I\'ve got to be careful ...            01/01/70 00:00      
                        Jan, you\'re missing my point!            01/01/70 00:00      
                           that's too easy to answer            01/01/70 00:00      
                              You have stories, but no specifics            01/01/70 00:00      

Back to Subject List