Are they preset to only return difficulty 1 shares when the find a nonce? Then mining software verifies if it meets current target difficulty? Or, if given a different target difficulty, will the ASIC only return shares that meet that difficulty setting?
If this is hardware specific, any idea which chips allow variation in the target difficulty?
The question in part stems from some misunderstandings I have seen on questions of what a share is. Whether it is always a nonce found for difficulty 1, or if it is a nonce found for the target difficulty sent to the miner. There are some confusing answers out there.