Re: [stella] TIA VSYNC and VBLANK

Subject: Re: [stella] TIA VSYNC and VBLANK
From: "Eric Ball" <ericball@xxxxxxxxxxxx>
Date: Tue, 5 Oct 2004 15:00:56 -0400
> VSYNC is used to generate the composite sync output SYN.  (how, exactly?
> is SYN simply VSYNC xor'd with the horizontal blank?)

Almost.  VSYNC causes the horizontal sync pulse timing to change from a
single ~4.7uS pulse per line to two ~27.3uS pulses per line.  These are the
"serration pulses" which cause the vertical retrace to occur.  (NTSC timing)

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