Aspects of the disclosure are related to a touch controller for use in a device having a processor and a touch sensor panel, the touch controller being coupled to the processor and the touch sensor panel, and further comprising: an analog front-end (AFE), wherein the AFE is configured to generate raw touch image data based on electrical signals generated by the touch sensor panel in response to one or more detected touches thereto; a coarse processing element configured to, in response to the processor being set to a sleep mode, coarsely process the raw touch image data to generate sparse data; and an embedded memory configured to store at least the sparse data.
