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

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
12/01/12 21:25
Modified:
  12/01/12 21:39
Read: times


 		 #188937 - Apparently several C8051F2xx parts have the same pinout
Responding to: ???'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            01/01/70 00:00      
   another solution            01/01/70 00:00      
   The probabilities are low...            01/01/70 00:00      
      think about what happens when you add a finger            01/01/70 00:00      
         The point is ...            01/01/70 00:00      
            Yes ... the underlying issue is the flash ...             01/01/70 00:00      
               Out of my office, but...            01/01/70 00:00      
                  Don't think in Vcc, ESD or hum...            01/01/70 00:00      
   Apparently several C8051F2xx parts have the same pinout            01/01/70 00:00      
   Characteristic for in system programmable flash micros...            01/01/70 00:00      
      All too true ... sadly ...             01/01/70 00:00      
         Power-on slope rate...            01/01/70 00:00      
            Sorry, my post should be here, no up there...            01/01/70 00:00      
            Have you any basis for that rate?            01/01/70 00:00      
               Vdd ramp time            01/01/70 00:00      
               Some datasheets show numbers...            01/01/70 00:00      
                  Those aren't the "usual" 805x-core MCU's            01/01/70 00:00      
                     There aren't many "usual" 8051-cores anymore...            01/01/70 00:00      
                        How dangerous power ups can be...            01/01/70 00:00      
                           I believe it            01/01/70 00:00      
                              (dV/dt) examples            01/01/70 00:00      
                                 They don't know it either...            01/01/70 00:00      
                                    dV/dT etc             01/01/70 00:00      
                                       reset request...            01/01/70 00:00      
                                          That's what disturbs me greatly            01/01/70 00:00      
                                             It IS disturbing!            01/01/70 00:00      
                                                Where this began ... at least for me ...             01/01/70 00:00      
                                                   So, you took the hard road...            01/01/70 00:00      
                                                      We've all had that experience             01/01/70 00:00      
   probable cause            01/01/70 00:00      
      Brent, this is very nice            01/01/70 00:00      
         forum no longer down            01/01/70 00:00      
      Thank you!            01/01/70 00:00      

Back to Subject List