A display driver includes a GRAM, a data driver, and a control circuit. The data driver is configured to: update, in a first mode, display elements of a display panel based on a command provided to the display driver asynchronously with a display vertical sync signal; update, in a second mode, the display elements based on image data stored in the GRAM in synchronization with the display vertical sync signal; and update, in a third mode, the display elements in synchronization with an external vertical sync signal. The control circuit is configured to: switch the display drive to a second mode in response to a first command; adjust, in the second mode, the display vertical sync signal based on an external vertical sync signal; and switch the display driver to the third mode after achieving synchronization of the display vertical sync signal with the external vertical sync signal.