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16f877a fried?

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jacob.zurasky

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I measure 80 ohms between (+) and (-) on one side and about 40 ohms between (+) and (-) on the other side. The chip seems to run fine at 5v, but when it is supplied with 3.3v it drops down to around 1.5v. Did I fry this one do you think?
 
As it works fine at 5V it seems unlikely that it's damaged, measuring across the supply pins on ohms doesn't really tell you very much!.

If the voltage is being pulled down when fed from 3.3V, it's more likely the 3.3V supply isn't able to supply enough current - try measuring the current it's taking!.
 
The resistance measurement was taken with the chip removed from the circuit board. A new 16f877a shows no conductivity between + and -. I was powering it off of an Ipod which worked previously with the 3.3v output from the dock connector. Should there be that low of resistance between those pins when not in circuit though? -Jacob

One other question Nigel, would there be a problem sending 5v rs232 signals to the 3.3v ipod rs232 port if I decide to use the 5v supply for the uC?
 
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