Fried Mega48 runs fine in STK500 but not otherwise

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#1
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Okay, I inserted my mega48 into my solderless breadboard wrong and accidentally put +5V to PD4 and GND to Vcc.

Now, when I put the Mega48 in correctly, PD4 is the only pin that goes high. The MCU doesn't seem to be running the program.

If I put the MCU in the STK500, however, it works as if nothing is wrong.

Any ideas, or has anyone had this happen to them before?

I'd test it with another Mega48, but I don't have anymore at the moment. :oops:

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As a guess the breadboard does not have a clock??? PD4 may have been damaged, I have a 8515 with 1 blown pin the rest works well, only use it around the workshop for >>risky<< operations..

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Maybe the shock changed the clock fuses and the chip need an external clock now. The STK500 provides clock. Try pulling the clock jumper and see if the chip still works.

Did you check the fuse settings ?

Markus

Markus

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Yep, fuse settings are still correct, and I have OCSEL and XTAL jumpers unconnected.

Correct, the breadboard does not have a clock source.

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Wow, I'm a smart one.

Mental note - DOUBLE check chip orientation. I kept trying to power the MCU by applying 5V/GND to AREF/GND. No wonder my voltage regulator kept heating up. :roll:

Works great now, that I flipped it 180*. :mrgreen: Yay for noob mistakes. Thank you all for the suggestions.