In an embodiment, an initialization extension device may provide an extended initialization period to enable a processor to configure a device, for example, an application specific integrated circuit (ASIC), prior to entering an operating mode. The device may include a number of control registers that may be configured to default settings in a register initialization period commenced in response to a reset signal. The reset signal may also trigger an extension timer to countdown a timer extended initialization period. During the timer extended initialization period, the processor may write an extension control signal, e.g., an extension bit, to a register. An initialization extension unit may maintain the device in an initialization mode during the timer extended initialization period and/or while the register contains the extension control signal. The processor may configure the control registers for one or more operations the device may perform when it enters the operating mode.