Device such as expansion card, access control method of the expansion card, and a memory medium storing a program capable of being read by computer

摘要

A data process of high performance is realized while generating a reference clock of a predetermined frequency without being influenced by a frequency fluctuation of a data transmission clock which is supplied through an expansion bus. A micro-computer measures the frequency of the data transmission clock and sets a frequency of the reference clock which is generated by a PLL circuit on the basis of the measured frequency.