Display Control 1 Register

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Number $69
Readable Yes
Writable Yes
Short Description Layer2, ULA shadow, Timex $FF port
Bit Function
7 Enable the Layer 2 (alias for Layer 2 Access Port ($123B / 4667) bit 1)
6 Enable ULA shadow (bank 7) display (alias for Memory Paging Control ($7FFD / 32765) bit 3)
5-0 alias for Timex Sinclair Video Mode Control ($xxFF / 255) bits 5:0

ULA shadow screen from Bank 7 has higher priority than Timex modes, setting bit 6 to "1" together with one of the extended Timex graphic modes will result into classic ZX128 ULA mode using Bank 7 data.