| 摘要 |
PROBLEM TO BE SOLVED: To stably drive a data output by using a 1st control signal to control a high impedance state of a data strobe signal and using a 2nd control signal to control a point of time when a preamble period of the data strobe signal begins. SOLUTION: A data strobe signal controller 200 receives a cas latency signal, an output enable signal and a clock signal to generate control signals QS- PREAMBLE and QS-ENABLE to control a data strobe driver 300. When the control signal QS-PREAMBLE transits to a logical high level from a logical low level, a data strobe signal begins a preamble state. The control signal QS-ENABLE takes a logical low level for periods other than a data output period, the preamble period and a post-amble period and the data strobe signal reaches a high impedance state.
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