Author Topic: problem of loading program in P89V51RD2 due to float GND(PIN 5) of serial cable  (Read 2591 times)

Tanumoy

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Hello Sir/Madam
                         After reading some of the Post in the forum I found out using a multimeter that PIN 5 of serial cable has +10V with respect to pin 3 of serial cable so it may lead to a floating gnd problem in the ckt,and also the flash magic is unable to program the microcontroller its showing message box of reset option when i push start buttom but when i am pressing the reset buttom its not responding to it.
                                                Even I have a shock sensation felling when i touch the gnd terminal of the ckt(After joining the gnd of serial cable to the 5V Ckt GND)
                                                PLEASE help me to solve this problem.I am using a desktop PC.
                                                                                       Thanking You
                                                                                        Tanumoy                                               

Andy Ayre

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You shouldn't be getting any electric shocks from any circuitry. It's possible you have damaged the microcontroller using static electricity or the improper ground.

Andy
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Tanumoy

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Hello Andy
                         Ya I have a improper ground in my room( i.e no earthing is done) .Can this be a reason that when flash magic is telling to reset the device but when i press reset button, flash magic is not responding to it.
                          Please tell me if this may be a reason then i should do a earthing in my room or the problem may be some thing else.
waiting for your reply
Thanking You
Tanumoy

Andy Ayre

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I suggest you set up an anti-static workstation:

http://en.wikipedia.org/wiki/Antistatic_wrist_strap

http://en.wikipedia.org/wiki/Antistatic_mat

*After* you have done that discard your microcontroller as it is probably damaged, and get a brand new one from an authorized NXP distributor.
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