FabiaTech FB2631, User Manual

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FabiaTech Corporation
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DMA Channel Map
The equivalent of two 8237A DMA controllers is implemented in the FB2631 board.
Each controller is a four-channel DMA device that will generate the memory
addresses and control signals necessary to transfer information directly between a
peripheral device and memory. This allows high speeding information transfer with less
CPU intervention. The two DMA controllers are internally cascaded to provide four
DMA channels for transfers to 8-bit peripherals (DMA1) and three channels for
transfers to 16-bit peripherals (DMA2). DMA2 channel 0 provides the cascade
interconnection between the two DMA devices, thereby maintaining IBM PC/AT
compatibility.
The following is the system information of DMA channels:
DMA Controller 1 DMA Controller 2
Channel 0: Spare Channel 4: Cascade for
controller 1
Channel 1: Spare Channel 5: Spare
Channel 2: Spare Channel 6: Spare
Channel 3: Spare Channel 7: Spare