View source for Copper Control Register

{{NextRegister
|Number=$62
|Readable=No
|Writable=Yes
|ShortDesc=Holds high byte of [[Copper]] control flags.
}}
{| class="wikitable"
|-
! Bit !! Function
|-
| 7-6 || Control mode
|-
| 5-3 || Reserved, must be 0
|-
| 2-0 || High three bits of Copper list index (value 0-2047)
|}

When "Control mode" bits are identical with previously set ones, they are ignored - allowing for index change without restarting currently running Copper program.

Copper has internally 10 bit "program counter" register ('''CPC'''), going through 0-1023 values, executing Copper instruction from the list at memory position (CPC*2). This will cause the Copper program to loop automatically. To "halt" program (avoiding possible loop), use WAIT instruction with non-existent horizontal line, like "WAIT 63,511 = 0xFF, 0xFF".

To change control mode, the new value must differ from previous, the possible control modes are:
{| class="wikitable"
|-
! Bits 7-6 !! Control mode
|-
| %00 || STOP Copper (CPC is kept at current value)
|-
| %01 || Reset CPC to 0 and START Copper
|-
| %10 || START Copper (does resume at current CPC)
|-
| %11 || Reset CPC to 0 and START Copper, reset CPC at each video frame at (0,0) (top left pixel of PAPER area)
|}