Semiconductor integrated circuit and electronic equipment
First Claim
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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Accused Products
Abstract
In a semiconductor integrated circuit, a detection confirmation circuit sets the logical level of a second signal according to the logical level of a first signal observed after a lapse of a predetermined time since detection of insertion/removal of a cable for peripheral equipment. The semiconductor integrated circuit operates in a standby mode in which only the insertion/removal detection circuit operates if no cable for peripheral equipment is connected, in a repeater mode in which only PHY operates if a cable for peripheral equipment is connected and CPU is in the suspended state, and in a normal mode in which both PHY and LINK operate if a cable for peripheral equipment is connected and a CPU is in the operating state.
16 Citations
7 Claims
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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:
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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, and the 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. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A semiconductor integrated circuit adapted to detecting the cable connection status, comprising:
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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 is inserted and changing the logical level of the first signal to a second logical level if all cables are removed; a counter circuit for receiving the first signal from the insertion/removal detection circuit, and for starting pulse counting of a supplied clock signal at the time of a change of the logical level of the first signal, stopping the pulse counting once the pulse count value reaches a predetermined value, and setting the logical level of the second signal according to the logical level of the first signal at the time of stop of the pulse counting; and a clock generation circuit for starting generation of the clock signal at the time of a change of the logical level of the first signal and stopping the generation of the clock signal if the pulse counting is stopped and the first signal is in the second level or the second signal is in a predetermined logical level, wherein the second signal is output as a cable connection detection signal.
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Specification