UPB8238

NEe Microcomputers, Inc. fttIEC Jl,PB8228 J.I PB8238 8080A SYSTEM CONTROLLER AND BUS DRIVER OESCR IPTION The pPB8228/8238 is a single chip cOntroller and bus driver for 8080A based systems. All the required interface signals rrecessary to connect RAM, ROM and I/O components to a pPD8080A are generated. The pPB8228/8238 provides a bi·directional three·state bus driver for high TTL fan-out and isolation of the processor data bus from the system data bus for increased noise immunity. The system controller portion of the pPB8228/8238 consists of a status latch for definition of processor machine cycles and a gating array to decode this information for direct interface to system components. The controller can enable gating of a multi·byte interrupt onto the data bus or can automatically insert a RESTART 7 Onto the data bus without any additional components. Two devices are provided:. the pPB8228 for small systems without tight write timing constraints and the pPB8238 for larger sy...