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Richard Erlacher
12/01/12 14:25
Modified:
  12/01/12 14:39

Read: 968 times
Denver, Co
USA


 
#188937 - Apparently several C8051F2xx parts have the same pinout
Responding to: Daniel Contarino's previous message
... and from that I understand that pin 6 is the X1 input to the oscillator.

Since it's an input, I doubt it would source much current, so I doubt your finger could brown the board out.

Daniel Contarino said:
When touching pin 6 (XTAL1, input, high impedance) the clock stops. But, sometimes, with everything connected to ground (even my body), the program stops and it does not start even after recycling power! It is necessary to reprogram the part. It seems that the flash got corrupted by some high voltage spike and/or 50Hz hum.


Is that crystal case connected to GND? Is the board still connected to the programming port? What's the supply doing?

One more thing ... I note from the datasheet, that "There are six sources for putting the MCU into the reset state: power-on/power-fail (VDD monitor), external RST pin, software commanded, Comparator 0, Missing Clock Detector, and Watchdog Timer ... Figure 12.1 ..."

I suspect that your oscillator stops when you touch Pin 6. Whatever happens, may well be during or at least initiated by this RESET.

RE

List of 33 messages in thread
TopicAuthorDate
C8051F231 experiences      Daniel Contarino      11/30/12 14:43      
   another solution      Erik Malund      11/30/12 15:11      
   The probabilities are low...      Daniel Contarino      11/30/12 18:34      
      think about what happens when you add a finger      Richard Erlacher      11/30/12 22:55      
         The point is ...      Daniel Contarino      12/01/12 03:08      
            Yes ... the underlying issue is the flash ...       Richard Erlacher      12/01/12 11:28      
               Out of my office, but...      Daniel Contarino      12/01/12 14:05      
                  Don't think in Vcc, ESD or hum...      Daniel Contarino      12/02/12 09:24      
   Apparently several C8051F2xx parts have the same pinout      Richard Erlacher      12/01/12 14:25      
   Characteristic for in system programmable flash micros...      Kai Klaas      12/01/12 18:25      
      All too true ... sadly ...       Richard Erlacher      12/01/12 20:13      
         Power-on slope rate...      Kai Klaas      12/02/12 05:31      
            Sorry, my post should be here, no up there...      Daniel Contarino      12/02/12 09:58      
            Have you any basis for that rate?      Richard Erlacher      12/02/12 10:15      
               Vdd ramp time      Maarten Brock      12/03/12 06:15      
               Some datasheets show numbers...      Kai Klaas      12/03/12 07:05      
                  Those aren't the "usual" 805x-core MCU's      Richard Erlacher      12/03/12 17:43      
                     There aren't many "usual" 8051-cores anymore...      Kai Klaas      12/03/12 18:13      
                        How dangerous power ups can be...      Kai Klaas      12/04/12 06:20      
                           I believe it      Richard Erlacher      12/04/12 08:59      
                              (dV/dt) examples      Jim Granville      12/04/12 13:14      
                                 They don't know it either...      Kai Klaas      12/04/12 18:49      
                                    dV/dT etc       Jim Granville      12/04/12 21:39      
                                       reset request...      Kai Klaas      12/05/12 06:21      
                                          That's what disturbs me greatly      Richard Erlacher      12/06/12 00:19      
                                             It IS disturbing!      Kai Klaas      12/06/12 08:02      
                                                Where this began ... at least for me ...       Richard Erlacher      12/06/12 09:43      
                                                   So, you took the hard road...      Kai Klaas      12/06/12 10:41      
                                                      We've all had that experience       Richard Erlacher      12/06/12 16:23      
   probable cause      Brent Wilson      02/04/13 20:32      
      Brent, this is very nice      Erik Malund      02/05/13 06:38      
         forum no longer down      Maarten Brock      02/05/13 07:33      
      Thank you!      Daniel Contarino      02/05/13 15:04      

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