| 摘要 |
<p>Expandable memory system having add-on modules beginning at fixed address boundaries, e.g., 2K (K=1024), and having verification and authorization features. A non-volatile memory stores a bit corresponding to each 2K memory boundary. When an add-on program is authorized at a particular boundary address, the corresponding bit is set. The base program checks each bit and, if it is set, reads the first location of the corresponding add-on program. If the data read from the new module matches some reference, e.g., the boundary address itself, then program control branches to the add-on program. Additional verification features include cyclic redundancy checks of the added code. Alternative operation includes branching to a verified add-on program that tests its own authorization bit which, if reset, causes a branch to the next verified add-on program, and so on. B09-77-070</p> |
