Editing Zilog Z80 (section)

=== Early history ===
At [[Fairchild Semiconductor]], and later at [[Intel]], [[physicist]] and [[engineer]] [[Federico Faggin]] had been working on fundamental [[transistor]] and [[semiconductor]] manufacturing technology. He also developed the basic design methodology used for memories and [[microprocessor]]s at Intel and led the work on the [[Intel 4004]], the [[Intel 8080]] and several other ICs. [[Masatoshi Shima]] was the principal logic and transistor-level designer of the 4004 and the 8080 under Faggin's supervision, while [[Ralph Ungermann]] was in charge of custom [[integrated circuit]] design.{{sfn|Faggin|Shima|Ungermann|2007|p=1}}

In early 1974, Intel viewed microprocessors not so much as products to be sold on their own but as a way to sell more of its main products, [[static RAM]] and [[ROM]]. A reorganization placed some of the formerly independent sections under the direction of Les Vadasz, further diluting the microprocessor's place in the company. That year, the [[1973–1975 recession]] reached a peak, and Intel laid off several employees.{{sfn|Faggin|Shima|Ungermann|2007|p=1}} All of this led to Faggin becoming restless, and he invited Ungermann out for drinks and asked if he would be interested in starting their own company. Ungermann immediately agreed, and as he had less to do at Intel, he left in August or September, followed by Faggin, whose last day at Intel was Halloween 1974.{{sfn|Faggin|Shima|Ungermann|2007|p=2}} When Shima heard, he asked to come to the new company as well, but having no actual product design or money, they told him to wait.{{sfn|Faggin|Shima|Ungermann|2007|p=3}}

The newly formed and unnamed company initially began designing a single-chip [[microcontroller]] called the 2001. They met with [[Synertek]] to discuss fabrication on their lines, and when Faggin began to understand the costs involved, it became clear that a low-cost product like this would not be able to compete with a design from a company with its own production lines, like Intel. They then began considering a more complex microprocessor instead, initially known as the Super 80, with the main feature being its use of a +5&nbsp;V bus{{sfn|Faggin|Shima|Ungermann|2007|p=3}} instead of the more common −5, +5 and 12&nbsp;V used by designs like the 8080. The new design was intended to be compatible with the 8080, but add a number of the features of the [[Motorola 6800]], including [[index register]]s and improved [[interrupt]]s.{{sfn|Faggin|Shima|Ungermann|2007|p=4}}