A touch I/O device controller may operate in an idle state, a wait for finger on state, and a finger on state. The finger on state may include a hold sub-state, a capture sub-state, a navigation sub-state, and a pre-capture sub-state. The controller may switch states and/or sub-states based on commands received from its host or based on a sub-state variable set by the host. When the controller detects a finger of a user and enters the finger on state, the touch I/O device may enter a particular sub-state based on the sub-state variable. Further, when a fingerprint is captured in capture sub-state, the controller may switch sub-states based on the value of the sub-state variable. In various implementations, the host may provide one or more APIs that may be utilized by applications to directly influence the controller and/or request that the host do so.