of Space Invaders by Zaccaria called The Invaders (the original by Taito uses an Intel 8080 CPU). Italian game manufacturer Zaccaria released 28 pinball machines based on the 2650 CPU. Their successor company, MrGame, released four additional pinball machines using the 2650. Zaccaria seems to have licensed its design to Technoplay as well, and several more pinball machines were released using variations of Zaccaria's circuit board designs. At least two coin-operated video games were released in the 1980s using the 2650. Hunchback, and Hunchback Olympic. The processor was also used in the Signetics Instructor 50, which was a small computer designed to teach the use and programming of the Signetics 2650 CPU. The 2650 was also used in some large items of equipment such as the Tektronix 8540, a microprocessor software development system which supported various in-circuit emulator, trace memory and logic analyser cards for real-time debugging of microprocessor systems, as practiced in the 1980s. The 2650 provided the base operating system functions, data transfer, and interface to a host computer or serial computer terminal. The processor was most suited as a microcontroller, due to its extensive I/O support: Single bit i/o pins on the processor (sense/flag bits) Signals to directly address two 8-bit I/O ports (control and data ports) using single byte instructions (port i/o). This circumvented the elaborate hardware other systems needed for memory-mapped I/O Signals to address another 256 I/O ports using an 8-bit address and two byte instructions, again, limiting the amount of hardware (address decoding) required. Philips emphasized this use as a micro-controller with a demonstration program showing the 2650 controlling an intelligent elevator system. Also, at trade fairs they showed the 2650 controlling a miniature 'sort and stack' robot Industrial Microcomputer System – IMS For a short time starting 1979, Philips sold a modular 2650 computer called the 'IMS' Industrial Microcomputer System, based on the Eurocard format in a 19" rack. It included CPU, PROM, RAM, input, output and teletype modules. This system was meant as a more intelligent programmable logic controller. For development, they later added DEBUG, DISPLAY, INTERRUPT and MODEST ((E)PROM programmer) modules. Architecture The 2650 was supplied in a 40 pin plastic or ceramic DIL enclosure. An external single phase clock signal and a single 5V supply were needed. The 2650 had many unusual features when compared to other microprocessors of the time: It was a fully static NMOS 8-bit microprocessor.