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Atmel Programmer

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ok i built the above programmer using an at90s2312 also completed crystal circut......

anyhow long story short, i can read security descriptors, but anything else failes the led also never lights up, the par port is giving me 4.6 volts and

96ma but the power drastically drops when i run an action, vcc to the atmel only carries 2.1 volts or so ...

Any ideas? been over the circut 30 times it matches......

Reply to
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I'm not completely sure what you mean here.

Is the HC244 supposed to get it's VCC on pin 20 through the diode D1 from the target circuit?

If so, is the target circuit powered up?

Reply to
Alan Kilian

yep i'm dumping 5v from the target circut to vcc, ponyprog allways fails on read/write etc....

basically my layout for the programmer is the same, i'm breadboarded so i wired from the 244 to my atmel and am supplying 5v to the vcc on the atlmel and back to the 244, the programming led goes on when i try to do something but nada, unfortunatly it's an old atlmel i dug up there is a possibility that it was previously fried .......

Reply to
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Couple of things to check.

  1. Make sure that the diode is good
  2. Check that capacitor. It's there to filter out hi frequency noise
  3. Check all grounds and be absolutely sure that they are connected.
  4. Next power up the whole thing (programmer, computer and target) Check: a. Power on Target circuit (vdd at the anode of the diode) b. Power on the programmer (vcc at pin 20) c. voltage on Pin 11 of the programmer. It should be close to 5v. The resistor is a weak pull-up resistor. You may have to put that pin on a scope.

If everything above check out good, replace the target chip with a known good one.

Good luck

---Keith Lehman

Reply to
Mad Jesuit

where are you getting your +5V from?

Don...

Reply to
Don McKenzie

Lol, it's all fine now, i simply had to move something away from then vcc on the 244 which was sucking some power and she runs no prob

Thanks :)

Reply to
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