Changes

The HSYNC and VSYNC signals from the CRTC are not directly connected to the display. They are passed to the [[Gate Array]] for further modification. See its wiki page.

On all CRTCs, while a VSYNC is ongoing, the condition VCC=R7 is ignored. So we cannot trigger a new VSYNC during a VSYNC. Similarly, we cannot trigger a new HSYNC during an HSYNC.