Abstract: A multi-mode IC is provided for operating in a first mode such as an ISO mode in accordance with International Standards Organization 7816 (ISO 7816) protocol, and a second, non-ISO mode, such as a USB mode in accordance with Universal Serial Bus (USB) protocol. The multi-mode IC is preferably in a smart card and includes a microprocessor and an external interface. The external interface comprises a voltage supply pad, a ground pad, a first set of pads for the first mode, and 2 second set of pads for the second mode. The first set of pads preferably include a reset pad, a clock pad and an input/output pad in accordance with the ISO 7816 protocol, and may also include a variable supply voltage pad in accordance with the ISO 7816 protocol. The IC further includes a mode configuration circuit for detecting a mode condition on one pad of the first set of pads, and configuring the IC in the ISO mode or the non-ISO mode depending on the result.

Abstract: A method and apparatus is disclosed for communicating with a host. In one embodiment, a smart card has an IC with voltage conditioning circuitry and a pull-up resistor. The smart card, when inserted in a smart card reader coupled to the host, is capable of signaling the host over a bus using the pull-up resistor selectively coupled to a voltage output of the voltage conditioning circuitry and a first output of the smart card. The voltage conditioning circuitry output is selectively coupled to the first output through the resistor, responsive to the device being powered by the bus but not transmitting. This tends to pull up the first output to the voltage level of the voltage source, which makes the smart card capable of being properly detected by the host upon the bus being driven by a host. Selectively disconnecting the pull-up resistor while the smart card is transmitting or receiving results in a more balanced differential output signal.

Abstract: A method and apparatus is disclosed for communicating with a host. In one embodiment, a smart card has an IC with voltage conditioning circuitry and a pull-up resistor. The smart card, when inserted in a smart card reader coupled to the host, is capable of signaling the host over a bus using the pull-up resistor selectively coupled to a voltage output of the voltage conditioning circuitry and a first output of the smart card. The voltage conditioning circuitry output is selectively coupled to the first output through the resistor, responsive to the device being powered by the bus but not transmitting. This tends to pull up the first output to the voltage level of the voltage source, which makes the smart card capable of being properly detected by the host upon the bus being driven by a host. Selectively disconnecting the pull-up resistor while the smart card is transmitting or receiving results in a more balanced differential output signal.