An integrated circuit device such as a structured ASIC includes a mask-programmable portion and a post-fabrication-programmable portion. The mask-programmable portion includes circuitry that is able to read information from the post-fabrication-programmable portion and use that information to affect operation of other componentry of the mask-programmable portion. Signal timing is an example of the kind of operation that may be affected by the above-mentioned information, which may allow post-fabrication timing tuning of the device.