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Semiconductor integrated circuit and electronic equipment

  • US 7,565,473 B2
  • Filed: 04/14/2006
  • Issued: 07/21/2009
  • Est. Priority Date: 04/14/2005
  • Status: Expired due to Fees
First Claim
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1. A semiconductor integrated circuit adapted to switching an operation mode thereof according to cable connection status for peripheral equipment and operation status of an internal or external CPU, the circuit comprising:

  • a low-level interface for transmitting/receiving a signal to/from a cable for peripheral equipment; and

    a high-level interface for performing communication between the low-level interface and the CPU,wherein the low-level interface comprises;

    an insertion/removal detection circuit for outputting a first signal, and for changing a logical level of the first signal to a first logical level if at least one cable for peripheral equipment is inserted and changing the logical level of the first signal to a second logical level if all cables for peripheral equipment are removed; and

    a detection confirmation circuit for receiving the first signal from the insertion/removal detection circuit, and for setting a second signal at a first logical level if the first signal is in the first logical level after a lapse of a predetermined time from a change of the logical level of the first signal, and setting the second signal at a second logical level if the first signal is in the second logical level, andthe semiconductor integrated circuit operates in a first mode in which only the insertion/removal detection circuit operates if the second signal is in the second logical level, operates in a second mode in which only the low-level interface operates if the second signal is in the first logical level and the CPU is in a suspended state, and operates in a third mode in which both the low-level interface and the high-level interface operate if the second signal is in the first logical level and the CPU is in an operating state.

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