On Thu, Jun 07, 2012 at 09:22:51PM +0300, Pasi 'Albert' Ojala wrote: > On 06/07/12 16:41, Gábor Lénárt wrote: > >resistor). In forums people say it's called "parasite power" that > >it can work even without Vcc connected, if the MCU can get power > >from other pins. However it sounds very strange for me, and > >honestly I can't understand this. > There are protection/clamp diodes from each input/output pin to gnd > and to vdd. If the voltage in the IO pin is above VDD+threshold > (0.6V), the diode starts to divert the current to protect the pin. > So, you can power a chip from its input pins, although it is not > recommended and not good for the chip. Ahha, thanks for the information! After I programmed FUSE bits in ATmega8A for Brown-Out-Detection, then this does not happen. Anyway, the lesson (for me at least): just not powering a chip, does not mean that you disabled it :) Message was sent through the cbm-hackers mailing listReceived on 2012-06-08 09:00:05
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