I2C(also IIC; the "2" is superscripted) Inter-Integrated Circuit Bus -- A moderate-speed serial communications bus originally invented by Philips in the early 1980s for consumer-electronics applications, such as inter-chip communication in a television set or high-end stereo.	 The I2C bus has recently appeared on PCs in video capture boards and similar devices, as well as (surprisingly) SDRAM DIMMs (for the on-board serial EEPROM).  The ACCESS.bus is a derivative of the I2C bus which forms the physical layer of the Universal Serial Bus.	 Similary, the SMBus (System Management Bus) also uses I2C as its physical layer. 86h/D8h - ITT VPX 32xx - VREF/HREF Control


Bitfields for VPX 32xx VREF/HREF control:
Bit(s)	Description	(Table I0036)
 0	reserved
 1	HREF polarity (=0 active high, =1 active low)
 2	VREF polarity (=0 active high, =1 active low)
 5-3	length of HREF pulse (+2 clocks)
 6	PREF select
	0 odd/even flag
	1 Pintr (programmable interrupt)
 7	PREF polarity (=1 invert polarity)
Note:	the Stealth64 Video 2001TV uses the PREF output to control the
	  audio signal; set bit 6 to select programmable interrupt on PREF,
	  then set bit 7 to mute, clear bit 7 to enable sound