4 ms·
A fun thing that I haven't seen anyone try is to deliberately induce metastability into a small circuit. Anyone who's played with digital logic knows that under
by eyegor 7y ago
A fun thing that I haven't seen anyone try is to deliberately induce metastability into a small circuit. Anyone who's played with digital logic knows that underpowering/overclocking will lead to unpredictable behavior. Just build an oscillator and aim for an unstable clock speed (beyond the spec'd setup/hold delays) with an inadequate power source.
- titzer 7y agoThere are already hardware random number generator products that are better (https://en.wikipedia.org/wiki/Hardware_random_number_generator https://en.wikipedia.org/wiki/Hardware_random_number_generat...). A key point is to reduce energy consumption. Instead of aiming for an unstable clock speed (which requires a lot of power), it suffices to sample the very small leakage current from some circuit at high precision.
- eyegor 7y agoUnstable clock speeds and power have zero relationship when you design the circuit. You can easily design something with a few transistors that will violate setup and hold times at 1-10mhz, which you can get out of a very low power crystal. You could even use an off the shelf mcu with a low nominal clock speed and just point a fast resonator at it. You can even make things unstable by giving it too slow of a clock speed. Most semiconductors don't want to hold a charge difference for very long.