18. The method of claim 13 , further comprising: detecting a first power state; operating in the first mode when in the first power state; detecting a second power state; and operating in the second mode when in the second power state.
18. The method of claim 13 , further comprising: detecting a first power state; operating in the first mode when in the first power state; detecting a second power state; and operating in the second mode when in the second power state. 19. The method of claim 18 , wherein: detecting the first power state comprises determining that power is not being received from an external source; and detecting the second power state comprises determining that power is being received from an external source.