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Problem while programming P89V51RD2

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Advanced Member level 4
Apr 15, 2011
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Chennai, Tamil Nadu, India
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I could not program my P89V51RD2, since there is a serial communication program already. When i am burning my new program, it shows that the COM port is already in use....i tried to hold my reset button but i failed..Please help....

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check if you have opened any other application which is using comport. like hyperterminal or any other program... close all the application and try again.. or a PC restart should do....

There is no other program is open other than flashmagic .... Since there is a program of serial communication is running...i couldnt use the COM port because my microcontroller already using it...

what is controller using the comport for.... stop the serial communication program if you are using hyperterminal or any other application for that purpose or go to task manager and see if any process is open or using it .... dont see the application..... see the process... or go to device manager and see if you can rename the comport to some other name and use it....

when i switch on the controller for programming, it starts sending a data through serial port(The program inside that is written to do so), so that it shows the port is busy while i am programming. i restarted my laptop several times and checked. and i check the process too.And i cant change the COM port since i am using a USB to serial converter. I replaced my microcontroller and i can able to use it now....Suggest any solution so that i can save one of my controller.


That is not possible... because by default it has to go to programming mode.. it is not because of a program.. maybe the EA pin is not getting proper voltage..... i have used so many time but never came across this fault.. maybe the bootloader problem..

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