Patent ID: 6839570

Claim:
A circuit for interfacing a modem in a Wireless Communication Device (WCD) to a Subscriber Interface Module (SIM), the SIM including an Input/Output (I/O) port for transmitting and receiving serial data, and a clock input for receiving a SIM clock, comprising: a modem controller; a Universal Asynchronous Receiver/Transmitter (UART) connected to the modem controller, the UART including a transmitter and a receiver to respectively transmit data to and receive data from the SIM I/O port over a common data line; and a programmable clock circuit adapted to generate the SIM clock and the UART clock based on a common clock provided to the programmable clock circuit, the programmable clock circuit being adapted to generate the SIM clock and the UART clock independently of one another in response to a clock control signal from the modem controller.