Microcomputer with high density ram in separate isolation well on single chip

An integrated circuit chip comprising an on-chip logic circuitry and an on-chip writable memory on a single integrated circuit chip having a substrate of semiconductor material of a first type, wherein said on-chip writable memory comprises a high density array of memory cells having at least one K bytes of storage, said integrated circuit chip including

• (a) memory array access circuitry on said chip;
• (b) a plurality of additional on-chip transistors comprising circuitry operable independently of the operation of said memory array;
• (c) a first isolation region on said chip, said first isolation region containing all of said memory cells of said high density memory array;
• (d) a second isolation region on said chip separate from said first isolation region, said second isolation region containing some of said additional transistors which are operable independently of said operation of said memory array, and
• (e) an isolation interface between said first and second isolation regions, said second isolation region being located adjacent said isolation interface, whereby said high density memory array is located on the same chip as said independently operating additional transistors and is protected from noise due to independent operation of said additional transistors.