Motorola MVME172 - Manual (Page 272)

4-36 Computer Group Literature Center Web Site
IP2 Chip
4
DEN Setting the DEN bit to a one will enable the DMA
function. Software should not write to the DMA control
registers between the time the DEN bit is set and the DMA
process is completed. In general, this is true on a per
channel basis but there are inter-relationships between the
DMA channels/board architecture which require the
initialization of certain bits for each pair of DMA
channels before the DEN bits can be set. That is, if DMA
channels a and b are going to be used concurrently, DMA
Control Register 1 should be initialized for both channels
before ether channel is enabled. This is also true for DMA
channels c and d. Refer to the section on the DMA Enable
Function.
OPER R R R R R R R S
RESET 0 R 0 R 0 R 0 R 0 R 0 R 0 R 0 R
ADR/SIZ $FFFBC022, $3A, $52, $6A (8 bits each)