| 摘要 |
PROBLEM TO BE SOLVED: To divide and display write and read cycles in a source synchronous bus. SOLUTION: Each of DQS and DQ of each of read and write cycles is received by a different channel of a waveform display device. In the next step, idle time before a burst signal in the DQS of the read or write cycle is detected, a trigger is applied in a first part of a burst signal, and the frequency of the burst signal is measured. Next, using the measured frequency, an estimated edge position of the DQ of each of both cycles with respect to an edge position of the burst signal is determined. Using the phase relationship between the edge position of the burst signal and the estimated edge position of the DQ is used, a trigger is applied to the DQS of each of the read and write cycles with a setup/hold time contravention trigger, and then each amplitude is measured. Then, using the difference between the amplitudes of the DQSs of respective cycles, the waveform of DQS or DQ related to one selected cycle is displayed. COPYRIGHT: (C)2009,JPO&INPIT
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