P89V51RD2 problem during reset

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P89V51RD2 problem

I am using P89V51RD2. For ISP there is no problem. When i do ISP my code runs properly, but after RESET (by pressing RESET switch or Power on RESET ) code does not run. Please tell me the solution to come in user code after RESET.

 

[Somphorn]

Re: P89V51RD2 problem

If not already done...

1) connect pull-up resistor 4K7 from ALE to VDD.

2) connect resistor 8K2 from RST to VSS. and connect 10uF electrolytic from RST to VDD.

As far as code is concerned, a reset will always cause the instruction pointer to start execution from location 0000H. If your code runs the first time, then I think it shouldn't be a problem after a reset.

But don't take my word for it. I'm not an expert in this.

 

[pratyathedon]

Do this values of resistor and capacitor matters.
i mean that if i use a 10k resistor instead of 8k2 and 10uf/35v instead of 10uf/16v does it will have any problem

 

[welove8051]

hello

pratyathedon:
the value you choose is of no problem.

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what is the code you are running. are you using serial communication. i had some problems when iam using serial communication program in rd2. if thats the case try to give some delay before serial communication in your program.

regards
kj
www.free8051projects.blogspot.com