1.
    发明专利
    未知

    公开(公告)号:DE3485686D1

    公开(公告)日:1992-06-04

    申请号:DE3485686

    申请日:1984-12-18

    Applicant: IBM

    Abstract: Data from a patch memory (23) is substituted for data in a read only memory (9) by applying high order addresses to a standard programmable logic array (19) having word lines (50a-50p, Figure 3). The address signals are separately applied to EXCLUSIVE OR circuits (27a-27g). The programmable logic array (19) is personalized to activate a line (21) at addresses to be substituted, and to provide logical zeros to the EXCLUSIVE OR circuits (27a-27g) which change during the patch. Only one word line is required for each continuous patch, which will vary in size on a patch-by-patch basis.

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