Patent ID: 8102401

Claim:
A display controller configured to couple to a microcontroller having a power-off mode, the display controller comprising: a first set of registers to receive and hold data from the microcontroller, the data including image data to be displayed on a display panel; a second set of registers loadable from the first set of registers; a set of multiplexers having first data inputs coupled to the first set of registers, second data inputs coupled to the second set of registers, and select inputs; and logic circuitry coupled to the output of the set of multiplexers and to the control inputs of the multiplexers, wherein the logic circuitry is configured to provide select information to the set of multiplexers and to provide waveforms to the display panel to selectively display data from the first set of registers and the second set of registers in accordance with the select information, and wherein the logic circuitry is configured to determine whether the microcontroller is in the power-off mode and, if the microcontroller is not in the power-off mode, load the data from the first set of registers to the second set of registers, and, if the microcontroller is in the power-off mode, provide select information to the set of multiplexers to alternately display on the display panel first image data in the first set of registers and different second image data in the second set of registers.