Dma Control - Commodore Amiga Hardware Reference Manual

DMA Control
Many different direct memory access (DMA) functions occur during system operation.
There is a read address as well as a write address to the DMA register so you can tell
which DMA channels are enabled.
The address names for the DMA register are as follows:
DMACONR - Direct Memory Access Control - read-only.
DMACON - Direct Memory Access Control- write-only.
The contents of this register are shown in table 7-5 (bit on if enabled).
212 System Control Hardware