Patent ID: 8436844

Claim:
A control circuit for controlling a bi-stable display comprising: a system controller, a display driver, a bi-stable segment monitoring module, and a charge pump, wherein: the charge pump is configured to generate one or more charge pump voltages; the bi-stable display comprises a plurality of bi-stable segments capable of transitioning between an on state and an off state with an application of the charge pump voltages; the display driver comprises a plurality of outputs that correspond to the plurality of bi-stable segments, and is operable to control individual ones of the plurality of bi-stable segments by applying the charge pump voltages to the plurality of bi-stable segments via the plurality of outputs in accordance with display instructions provided by the system controller; and the bi-stable segment monitoring module is operable to detect a bi-stable segment voltage level of at least one output of the display driver and compare the detected bi-stable segment voltage level of the output with a valid bi-stable segment voltage level of the output, wherein: the display driver is operable to provide a write operation completed signal to the system controller upon successful completion of the display instructions; the bi-stable segment monitoring module is operable to suppress the write operation completed signal if a detected bi-stable segment voltage level of an output does not equal the valid bi-stable segment voltage level; and the system controller is operable to provide an alarm if the write operation completed signal is not received within a period of time after providing the display instructions to the display driver.