1. A content addressable memory arbiter emulation circuit for providing field upgrade capability to an electronic system: a content addressable memory circuit having an address in terminal coupled to a request address line routing a direct address, an address out terminal, a match signal line, a set of configurable direct addresses, and a set of emulation addresses; and a multiplexer having a pass control terminal coupled to said match signal line, a first pass input terminal coupled to said address out terminal, a second pass input terminal coupled to said request address line, and a pass output terminal outputting an access address; a memory address line coupled to said pass output terminal having a first access connection to a block of memory and a second access connection to a block of configurable memory; wherein said content addressable memory circuit outputs a match signal on said match signal line and outputs a particular emulation address of said set of emulation addresses corresponding to said direct address on said address out terminal when said direct address is in said set of configurable direct addresses; wherein said multiplexer outputs said particular emulation address on said pass output terminal as said access address when receiving said match signal on said pass control terminal and outputs said direct address on said pass output terminal as said access address when not receiving said match signal on said pass control terminal; and wherein said memory address line selects one of replacement data from said block of configurable memory in response to said particular emulation address and original data from said block of memory in response to said direct address depending upon the value of said access address to be passed to an output data line.