Write-Protection Mechanism for Nonvolatile Random-Access Memory
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Microprocessors in use today can address vast memory spaces due to large numbers of address bits. For example, the Motorola 68000 has 24 address bits giving it an address space of 8 megabytes. In many current small systems, or microprocessor-driven subsystems much of this addressibility is extraneous. In addition to some memory, the typical design will contain several other chips to provide the other required function. Typically, these chips will each contain several registers which will be memory mapped. To save chip level I/Os it is convenient to partition the address range into several functions. Logic is included to decode pertinent address bits to generate chip selects. In this way each chip will look only at one chip select and the required low level address bits.