| 摘要 |
A programmable device, such as a field programmable gate array, includes a main field that is programmable by the user and at least one embedded portion that is reserved to be programmed with a standard circuit design that is configured, for example, by the manufacturer. The embedded portion is similar to the main field, i.e., it has the same programmable structure, however, the embedded portion is not accessible to the user. In some embodiments, the embedded portion may be pre-programmed with the standard circuit design and in other embodiments the embedded portion is programmed while the user programs the main field. The programmable device may also include signature bits that are used by the programming unit to identify the programmable device as having the embedded portion and which standard circuit design to program into the embedded portion. The signature bit may be programmed after the manufacture of the programmable device or may be hard wired during the manufacture of the device. The programming unit recognizes the configuration of the signature bits and restricts access to embedded portion based on the configuration. |
