The PIC16F628 is a 8-bit fully-static Flash-based CMOS Microcontroller. The PIC16F628 have enhanced core features, eight-level deep stack, multiple internal and external interrupt sources. The separate instruction and data buses of the Harvard architecture allow a 14-bit wide instruction word with the separate 8-bit wide data. The two-stage instruction pipeline allows all instructions to execute in a single cycle, except for program branches (which require two cycles). A total of 35 instructions (reduced instruction set) are available. Additionally, a large register set gives some of the architectural innovations used to achieve a very high performance. The PIC16F628 microcontroller typically achieve a 2:1 code compression and a 4:1 speed improvement over other 8-bit microcontrollers in their class. The PIC16F628 device have special features to reduce external components, enhancing system reliability and reducing power consumption.