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According to the documentation I have ("Hardware" by J.Schimanski) after setting the copper list COP1LCx under $dff080 it should be started by writing an arbitrary value into COPJMP1 under $dff088. However my copper list works "automatically" without the latter step. What is the right way of doing it? Do I need this starting step?

I use Amiga 500 with ECS.

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The Copper list is started automatically with every vertical sync. If you need it to start at some other time you need to write to COPJMP1.

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    Can you give me an example of "at some other time"? – Adam Boczek Dec 28 '17 at 12:39
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    Well, for example you could build separate Copper lists/viewports for several screens you'd want to display simultaneously (below each other). Without merging the separate viewport lists to a single, larger one, you could write each start address to COP1LC and then write to COPJMP1 to switch to that viewport. It's a bit like an unconditional JMP for the Copper, while writing to COP1LC alone just primes the vector for the next run. – Zac67 Dec 28 '17 at 12:55

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