RNG 的操作方式

Operation of RNG To run the RNG, follow the steps below: 1. Enable the interrupt if needed (to do so, set the IE bit in the RNG_CR register). An  interrupt is generated when a random number is ready or when an error occurs. 2. Enable the random number generation by setting the RNGEN bit in the RNG_CR  register. This activates the analog part, the RNG_LFSR and the error detector. 3. At each interrupt, check that no error occurred (the SEIS and CEIS bits should be ‘0’ in  the RNG_SR register) and that a random number is ready (the DRDY bit is ‘1’ in the  RNG_SR register). The contents of the RNG_DR register can then be read.

NOTE: A generated number required to compare with the previous one,   it fails  if turns out to be equal.