The PIC18F4620-I/P is an enhanced Flash Microcontroller with 10-bit A/D and nanoWatt technology. This offers ten different oscillator options, allowing users a wide range of choices in developing application hardware. This device offers a total of seven operating modes for more efficient power management. These modes provide a variety of options for selective power conservation in applications where resources may be limited. As Harvard architecture device, the data and program memories use separate busses; this allows for concurrent access of the two memory spaces. The data EEPROM, for practical purposes, can be regarded as a peripheral device, since it is addressed and accessed through a set of control registers.