NAME   rev ADDR type chip Description
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HTOTAL H  1C0  W  A    Highest colour clock count in horiz line


	BIT#  15  14  13  12  11  10  09  08  07  06  05  04  03  02  01  00
	       x   x   x   x   x   x   x   x  h8  h7  h6  h5  h4  h3  h2  h1

	(x`s should be driven to 0 for upward compatibility)
	Horiz line has theis many + 1 280nS increments. If the
	pal bit & LOLDIS are not high, long line/skort line toggle
	will occur, and there will be this many +2 every other line.
	Active if VARBEAMEN=1 or DUAL+1.