A display driver includes image processing circuitry, driver circuitry, and test circuitry. The image processing circuitry is configured to generate first output data during a first display update period and generate second output data during a second display update period. The driver circuitry is configured to update a display panel based on the first output data during the first display update period and update the display panel based on the second output data during the second display update period. The test circuitry is configured to test the image processing circuitry during a test period disposed between the first display update period and the second display update period.