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I am making a project using at89c51. I used my mobile charger (output: 5V, 1A) as the power supply. Will my IC get damaged due to the high current?

I asked cause, without loading the program I connected the pin40(Vcc) and pin20(gnd) just to check whether all the port pins except port0 give output 1 or not, which is as I believe by default. And I got haphazard values which changed everytime I turned the supply off and on.

I also couldn't find the supply current range in the datasheet so got more confused.

Please advise.

peterh
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Deep
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  • Nope, my problem is that by default the pins of port 1,2,3 are logic 1 when no program is loaded, which i didnt get, so i asked whether the supply is at fault. – Deep Sep 15 '14 at 10:29
  • If your charger gives 5V (check this), it should work. It will not always give 1A, that's just the maximum current that the charger can handle. The actual current is determined by the device you connect to it. That's explained in the link @PeterJ gave you. –  Sep 15 '14 at 10:45
  • Do you have EA at VCC? – venny Sep 15 '14 at 10:54
  • @venny, no i have not connected EA at Vcc. Is there any significane? – Deep Sep 15 '14 at 11:14
  • @Deep Yes, when EA is low, GPIO ports are used as external memory interface. – venny Sep 15 '14 at 11:40
  • @venny, ok so if i connect EA to vcc then pins of all ports 1,2,3 will be 1 by default if no program is loaded? – Deep Sep 15 '14 at 11:52
  • @Deep That is what I would expect. Maybe it will require functioning oscillator as well, if there is no internal one. – venny Sep 15 '14 at 12:05
  • @venny, i will try and revert back to you. – Deep Sep 15 '14 at 12:12
  • @venny, connected both the clock circuit as well as EA to Vcc. Problem still persists. – Deep Sep 16 '14 at 05:56

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