[quote:88b091e314]Atmel AVRs have an internal Power On Reset circuit.
Specific criteria must be met, or the POR circuit won't enable the micro to start running.
The voltage must be mono-tonic, (smooth, rising, no dips or glitches).
The rate of rise is also important, not too slow, not too fast. [/quote:88b091e314]
I deliberately tried many times to make an AVR ( several different models ) not start by doiing terrible things to the power supply. Never ever had one fail to start when the voltage finally came within spec. That was one of my original criteria for choosing AVR over several other processors. Means you dont need another voltage supervisor circuit to get it to start reliably.
I see nothing in the datasheet to suggest the AVR needs a critical rate of rise of power supply to make a reset, only the level has to meet certain criteria.
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