Intel AP-30 Application of Intels 5V EPROM and ROM Family Jan79 free download

File name AP-30_Application_of_Intels_5V_EPROM_and_ROM_Family_Jan79.pdf

APPLICAliON AP-30 inter NOTE 9000796A (c) Intel Corporation, 1979 Application of Intel's Contents 5V EPROM and INTRODUCTION ... 1 ROM Family for PINOUT EVOLUTION ... 1 Microprocessor SYSTEM ARCHITECTURE ... . . . . . . . .. 1 Systems BUS CONTENTION ... 2 THE MICROPROCESSOR/MEMORY INTERFACE ... 3 TERMINOLOGY ... 3 THE NEW INTEL FAMIL Y ... 4 PRINTED CIRCUIT BOARD DESIGN ... 6 Intel Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in an Intel product. No other circuit patent licenses are implied. INTRODUCTION This Application Note discusses how the new Intel family for the 32K devices must be derived from the 2716 in order of 5 volt EPROMs and ROMs can be used with micro- to maintain socket compatibility. This 16K to 32K pinout processor systems. The pinout evolution and philosophy evolution is shown in Figure 1. are explored in detail, which leads directly to system archi- tecture. Particular emphasis will be placed on the pitfalls of bus contention and the microprocessor/memory inter- face. Finally, an actual printed circuit board layout is presented. PINOUT EVOLUTION As EPROM/ROM technology has evolved, there are often periods of confusion over EPROM and ROM pin- outs, as ROM density usually leads EPROM density by a factor of two, but ultimately users want any given EPROM to have a ROM compatible part. As we have seen, after the 2716 16K EPROM was introduced, a new ROM pinout emerged and "triumphed" over an earlier "standard." The reason this ROM pinout change occurred is that as codes stabilize in user's systems and equipment, many users opt for the less expensive ROMs, which are mask Figure 1. 16K EPROM Determines programmable devices. At the same time, users often use 32K ROM Pinout the highest available density ROM so they combine modular fi