| 摘要 |
PURPOSE: A UART including a smart card interface is provided to use a UART and a smart card interface selectively by supporting a smart card interface function using a few hardware. CONSTITUTION: A smart card interface(39) consists of the second controller(40), a clock generator(41) and the second state(42), that is, four registers are appended. A register appended firstly out of the four registers is a clock generator(41). The clock generator(41) is used at a programmable clock generator and provides an external clock(clock out for smart card) to be supplied to a smart card. A register appended secondarily is the second state(42) displaying status of construction elements(stored data, digit and opening/closing of switch in a register) in a system. A register appended thirdly is the second controller(40) performing functions of selecting a mode(UART or smart card interface(39)), selecting an external clock supply or not and controlling an error detector enable. A register appended fourth is a PIO unit(37). The PIO unit(37) plays a role of a path for inputting/outputting of interface signals with the smart card. It is controlled whether the device is used as the UART or the smart card interface(39) using the second controller(40). If the device is used as the smart card interface(39), only asynchronous operation is possible and a card using an internal clock may be supported, and a clock may be supplied to a card using an external clock using a clock generator(41).
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