Texas Instruments - MSP430F1121

For serious low power designs we've found the MSP430 microcontrollers hard to beat, surpassing even the mighty PIC range from Microchip in some applications.

The MSP430 here is running from a watch crystal and is powered by a single coin cell. Unlike many other micros, the in-built timer can be run at full clock speed - there is no prescaler to reduce the resolution of the capture / compare functions. Capturing transitions on both the rising and falling edges of the 32kHz oscillator allows this design to resolve a 550Hz signal to 1% with power consumption down at 14uA - two years from a 2032 coin cell.