Redundant memory, data processor using same, and method therefor

摘要

A redundant memory (25) includes a main memory (30), a multiplexer (32), a cache (40), and a non-volatile memory (31) for storing control, address, and data values used by cache (40) in a tag (41) and a data portion (42). The redundant memory (25) supports data replacement on a word-by-word basis without impacting access time of the redundant memory (25). Accesses of the failing address access a data portion (42) of the cache (40). The multiplexer (32) selects the cache (40) when the access address matches the programmed address in cache (40), which allows for a fully functional main memory (30). For example a failing flash electrically erasable programmable read only memory (FLASH EEPROM) data word may be replaced by programming the FLASH EEPROM address within a non-volatile memory (31). The redundant memory (25) may be integrated into a data processor such as a microcontroller (20) which also includes a central processing unit (21) and on-chip peripherals (24). <IMAGE>