ISA DMA: Difference between revisions
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Finally, '''all''' DMA controllers run at 4 MHz. (Information taken from ISA Specification) '''No exceptions'''. |
Finally, '''all''' DMA controllers run at 4 MHz. (Information taken from ISA Specification) '''No exceptions'''. |
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Ignore that GHz tag on your processor or the fact that even PCI runs at 33 MHz. DMA controllers are fixed at this rate. This includes EISA and PS/2 32-bit DMA controllers. Some |
Ignore that GHz tag on your processor or the fact that even PCI runs at 33 MHz. DMA controllers are fixed at this rate. This includes EISA and PS/2 32-bit DMA controllers. Some of the differences between these and the stock ISA DMA controllers is a extra page register allowing for 64k transfers anywhere in 4 GiB of space and the ability to do 32-bit transfers, and these DMA controllers exists only on EISA and MCA systems, which are now obsolete and are not described here. |
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So after reading all the above, the main points are: |
So after reading all the above, the main points are: |