Patent ID: 7671624

Claim:
A packaged integrated circuit (IC) device, comprising: a first die including a masked-Read Only Memory (ROM) that is programmed during fabrication of the masked-ROM to store configuration data provided by a user; a second die including a programmable device having: configuration circuitry for selectively invoking a first configuration mode and a second configuration mode, the configuration circuitry receiving the configuration data from the masked-ROM in the first configuration mode and receiving external configuration data from an external controller in the second configuration mode; and a number of configurable resources collectively configured to implement a specified circuit design embodied by the configuration data or the external configuration data, wherein the first die is electrically connected to the second die, and wherein the first die and second die are stacked; a plurality of first conductive pads provided on the first die and electrically connected to the masked-ROM; and a plurality of second conductive pads provided on the second die and electrically connected to the programmable device, wherein corresponding pairs of the first and second conductive pads are electrically connected to one another, wherein the first conductive pads formed on the first die are not accessible from outside the packaged IC device.