Revision of Microcode Module in Read-Only Memory
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
This article describes a revision of a microcode module for a working terminal device stored in a read-only memory (ROM). Plural modules are stored in the ROM along with their module information including module identifier, priority, address data, etc. When it is required to revise one of the modules to a new module due to an engineering change, the new module and its module information with a next higher priority is stored in a new ROM. At power-on of the working terminal device, an initial set-up microcode module is called which determines the module information stored in the ROMs, to assemble a table for accessing the modules. Generally, the ROMs of the working terminal device store plural microcode modules each of which comprises a group of microcodes. Fig.