The CAT5251 is four Digitally Programmable Potentiometers (DPPsTM) integrated with control logic and 16 bytes of NVRAM memory. Each DPP consists of a series of resistive elements connected between two externally accessible end points. The tap points between each resistive element are connected to the wiper outputs with CMOS switches. A separate 8-bit control register (WCR) independently controls the wiper tap switches for each DPP. Associated with each wiper control register are four 8-bit non-volatile memory data registers (DR) used for storing up to four wiper settings. Writing to the wiper control register or any of the non-volatile data registers is via a SPI serial bus. On power-up, the contents of the first data register (DR0) for each of the four potentiometers is automatically loaded into its respective wiper control register.