No stop instruction is provided for the Copper. To ensure that it will stop and do nothing until the screen display ends and the program counter starts again at the top of the instruction list, the last instruction should be to WAIT for an event that cannot occur. A typical instruction is to WAIT for VP = $FF and HP = $FE. An HP of greater than $E2 is not possible. When the screen display ends and vertical blanking starts, the Copper will automatically be pointed to the top of its instruction list, and this final WAIT instruction never finishes. You can also stop the Copper by disabling its ability to use DMA for retrieving instructions or placing data. The register called DMACON controls all of the DMA channels. Bit 7, COPEN, enables Copper DMA when set to 1. For information about controlling the DMA , see Chapter 7, "System Control Hardware."