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Dell OptiPlex N Systems Service Manual
D
MA Channel Assignments
Table 1-4 shows the assignment or availability of DREQ lines.
Table 1-4. DREQ Line Assignments
DREQ Line
Used By/Available
DREQ0
Available
DREQ1
Available
DREQ2
Generated by super I/O controller to initiate DMA cycle for
attached diskette drive
DREQ3
Available
DREQ4
Generated by bus controller chip to activate second DMA
controller
DREQ5
Available
DREQ6
Available
DREQ7
Available
NOTES: The video controller and optional built-in NIC controller are assigned available
DMA channels automatically during computer start-up.
If the parallel port is in ECP mode, it uses one of the available DREQ lines.