At power-on or reset time, you must initialize one of the Copper
 location registers (cop1lc or cop2lc)  and write to its  strobe address 
before Copper DMA is turned on. This ensures a known start address and
known state. Usually,  cop1lc  is used because this particular register is
reused during each vertical blanking  time. the following sequence of
instructions shows how to initialize a  location register . it is assumed
that the user has already created the correct  copper instruction list  at
location "mycoplist."

;
; Install the copper list
;
     LEA     CUSTOM,a1           ; a1 = address of custom chips
     LEA     MYCOPLIST(pc),a0    ; Address of our copper list
     MOVE.L  a0,cop1lc(a1)       ; write whole longword address
     MOVE.W  copjmp1(a1),d0      ; causes copper to load pc from  cop1lc 
;
; Then enable copper and raster dma
;
     MOVE.W  #(DMAF_SETCLR!DMAF_COPPER!DMAF_RASTER!DMAF_MASTER),dmacon(a1)
;

Now, if the contents of  cop1lc  are not changed, every time
 vertical blanking  occurs the copper will restart at the same location
for each subsequent video screen. This forms a repeatable loop which, if
the list is correctly formulated, will cause the displayed screen to be
stable.