Making microcontroller RAM non-volatile

A cost-effective way of making some small capacity microcontroller RAM non-volatile is discussed. A software algorithm coupled with the reset circuit is used for the purpose. The reset circuit uses a special three-pin reset IC which has positive reset pulse required for the microcontroller. The power-on reset pulse is a normal pulse while the power-down reset pulse is dependent on the voltage fall slope. After reset, the microcontroller waits for a predefined delay time to allow all the voltages to fall to zero after power-down. The implementation of the algorithm consumes just a small program memory space.