YMF724B、YMF724C、YMF724E 的差異

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B版：DDMA（Distributed DMA）無法正常運作。

C版：已解決 DDMA 問題，但在 Intel BX 晶片組的主機板上 DDMA 仍無法正常運作。

E版：解決 Intel BX 晶片組的主機板上 DDMA 問題。

什麼是 DDMA？

DDMA is an alternative legacy DMA solution.This techniquee effectively "distributes" the 8237 DMA controller into physically separate PCI resident components on a per DMA basis.

A "Master DMA agent" central resource is located somewhere in the system which orchestrates the legacy I/O traffic to and from the distributed DMA elements of the system.The DMA master intercepts all 8237 I/O register references and redirects,via a software configured lookup,for control/status registers,combined data for all of its DMA channels within single I/O registers,the DMA master typically scatters and gathers several bus transactions to complete a single legacy I/O register read or write.