While border is active, all the CRTC counters continue to increment normally and addresses continue to be generated.
The DISPTMG signal is composited from its 3 internal subcomponents: HBORDER (Horizontal), VBORDER (Vertical), IBORDER (ImmediateInstant) by using the NOR function. DISPTMG is "0" if at least one of its subcomponents is "1". These 3 subcomponents are all independent of each other.
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=== Split border HBORDER === On all CRTCs, HBORDER is disabled when HCC=0 and enabled when HCC=R1. The exception is for CRTC2 during an HSYNC: the HCC=0 check is skipped, so HBORDER stays on. <br> === IBORDER ===
Split border is a technique similar to split rasters, except that it is handled by the CRTC instead of the [[Gate Array]].
BORDER 6:OUT &BC00,6:OUT &BD00,0
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=== Border and HSYNC ===
On all CRTCs, HBORDER is disabled when HCC=0 and enabled when HCC=R1.
The exception is for CRTC2 during an HSYNC: the HCC=0 check is skipped, so HBORDER stays on.
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