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Doubt about suppy to circuit Answered

+5V suppy connector was not  mentioned in schematic 

So I added that 
Please tell me whether it is right or wrong 
schematic and layout is attached below

Tags:Power

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gmoon
gmoon

9 years ago

Looks OK to me, assuming the polarity of the power jack / supply is correct.

It's been a little while since I've worked with AVRs, but generally when using a crystal as a clock source they require a capacitor pair (to GND, 10 to 40pF) to adjust the capacitive load of the xtal and assure it starts oscillating. I don't see that on your schematic. You may have an xtal with internal caps, but those are generally three-legged beasties.

Also, what's the point of the 10uF and 10K resistor in series? AVR circuits often place a 10uF cap between V+ and GND, just as an additional supply filter/buffer. But why the 10K resistor?

You may have referenced other AVR circuits where a 10K pullup (to V+) is used with the RESET pin, and simply misplaced the 10K. Regardless, the AT89C51 resets on HIGH, not LOW like newer AVRs, so you cannot use a pullup on RST here (which is not in your schematic anyways)...