WDC 65C02

The Western Design Center (WDC) 65C02 microprocessor is an enhanced CMOS version of the popular NMOS-based MOS Technology 6502 8-bit microprocessor—the CMOS redesign being made by Bill Mensch in 1978. Over various periods of time, the 65C02 has been second-sourced by NCR, GTE, Rockwell, Synertek and Sanyo. The 65C02 has been used in some home computers, as well as in embedded applications, including medical-grade implanted devices.

Introduction and features

The 65C02 is a low cost, general-purpose 8-bit microprocessor (8-bit registers and data bus) with a 16-bit program counter and address bus. The variable length instruction set and manually optimized core size are intended to make the 65C02 well suited for low power system-on-chip (SoC) designs.

The W65C02S–14 is the production version of the 65C02 microprocessor, and is available in PDIP, PLCC and QFP packages through distribution. The maximum officially supported ϕ2 (primary) clock speed is 14MHz, indicated by the –14 part number suffix. The "S" designation indicates that the part has a fully static core, a feature that allows ϕ2 to be slowed down or fully stopped in either the high or low state with no loss of data. Typical microprocessors not implemented in CMOS have dynamic cores and will lose their internal register contents (and thus crash) if they are not continuously clocked at a rate between some minimum and maximum specified values.