Hello PicWorld ! first, thanks to all for replying to this thread. i wanna generate some power glitchs, not for testing purpose like succeptibility to power input noise. i wanna 'take control' over some internal hardware/software execution. eg: skip a few instructions cycle, unload internals buffers, miss interrupt, ... i read all of your replys, but it's not exactly what i'm searching for ; too hazardous for me ! i see somewhere that if a chip is underpowered, it could be in a undefined state. it's the undefined state who interrest me. how to glitch from the normal state to undefined and back to normal state. i think make a real-time Up-power supply (PIC inside !), who could make spikes (and/or VDD,VGG,RST,CLK,IO,...). But, to affect one instruction cycle on a chip running at 10 Mhz(100 ns cycle), glitch timing must be very fast(~20 ns ?). by now, PICs are not fast enough to attack a DAC for generating a power slope, then i must use externals chips drived by a PIC, like delay lines or ? i see a similar application on the net using an atmel ATV750-30 (PAL) some ideas to do this will be great (forget piezo-lighter !) . ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com