摘要 |
A data security fuse system (35) for allowing one-time programmability of protected data cells in a reprogrammable logic device (10), which may determine, for example, the logic architecture of the device. The system includes a fuse enable circuit (100) which may be erased to the disabled state only prior to packaging of the device during manufacture. The protected data cells may be selected for programming by a decoder (30) which decodes cell selection signals. A security fuse circuit (300) is enabled by a fuse enable signal (SFE) from the activated fuse enable circuit. The security fuse circuit (300) allows the protected cells to be selected once for programming after the system has been activated, and thereafter defeats any attempts to access the protected data cells. |