The Design of Diode-Transistor NOR Circuits

Considerations leading to the adoption of diode-transistor NOR circuitry for a moderately fast data-processing system are outlined. The design of the basic circuit is treated in detail. Development of a unique set of compatible logic packages from the basic circuit is described. This set is unique in the sense that a single type of diode-transistor circuit is used to provide the great majority of logic and storage functions required in the system. This single circuit type, which functions as a NOR circuit, is embodied in two package types. One package provides a single gate with a fan-in of five. The other package provides two gates, each with a fan-in of two. The latter type may be externally connected to provide a set-reset flip-flop. Only two other package types are used. The first is a passive transfer circuit which greatly simplifies shift register logic, and the second is a delay package which is closely related to the basic NOR circuit.