Samsung Electronics Co., Ltd.

Hae-Jin Song

Yong-Mi Lee

Kab-Joo Lee

Jin-Tae Joo

The present invention provides semiconductor devices capable of being tested using one test pin and using an input/output pin without any test pins, and methods of testing the same. One semiconductor device comprises a test pin for inputting/outputting test data, an operation mode controller for activating an enable signal in response to an external reset signal and a clock signal, an operation mode storage for receiving serial data synchronized with the clock signal through the test pin in response to the enable signal, and an operation mode decoder for generating operation mode selection signals in response to the serial data stored in the operation mode storage. Another semiconductor device comprises an input/output pin for receiving test data, a delay reset signal generator for delaying a reset signal, a counter for counting a clock signal in response to the reset signal to generate a counted value, a mode register for storing the test data, and a decoder for generating selection signals to the mode register to designate a position in the mode register where the test data is written.

Semiconductor device tested using minimum pins and methods of testing the same

There is provided a media access controller with a power-save mode. Particularly, the media access controller of the present invention minimizes power loss by disabling clocks applied to all blocks, including CPU, of the media access controller during the power-save mode. The media access controller of the present invention includes: a power-save master for securing stable transmission/reception of data through bus by respective processors contained in the controller; a wake-up timer for noticing that the power-save mode is expired; a power control unit for determining whether to supply a power to a phase-locked loop, and a timing when clocks for the media access controller are applied and disabled; and a locktime register for storing a locktime when an output of the phase-locked loop is settled. Additionally, there is provided a method of efficiently changing the media access controller from the active mode to the power-save mode, and vice versa.

Media access controller with power-save mode

In a clock switching apparatus, a corresponding mask clock signal is generated for at least one of first and second clock signals. A mask clock signal has an interval of a predetermined logical level near the switching between the clock signals. Each mask clock signal is synchronized to the first and/or second clock signals. Such an interval in the mask clock signal prevents occurrence of glitches in an output clock signal that is switched between at least one mask clock signal and/or at least one clock signal.

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Seongnam-si, South Korea

Hae-Jin Song