AMD Geode SC1200 Data Book page 358

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Table 7-9. F4BAR0+Memory Offset: Video Processor Configuration Registers (Continued)
Bit Description
Offset C2Ch-C2Fh
31:7 Reserved.
6 TV_DAC_TEST (TV DAC Glitch Test). When this bit is asserted, the TV DACs operate in Test mode.
5 PDN (Power Down). When asserted, the TV DACs are placed in power-down mode.
4:3 VREF (VREF Select). Selects the source for the voltage reference for the TV DACs.
00 & 01: Select internal bandgap reference.
10 & 11: Select external voltage reference.
2:0 TRIM. The value in this field is used to adjust the internal voltage reference.
Offset C50h-C53h
31:17 Reserved.
16 VBI_TEST_MODE (VBI Test Mode). Precoded data (a square wave) sent as VBI data.
0: Not precoded VBI data.
1: Precoded VBI data.
15:8 VBI_SCALE_GAIN (VBI Scale Gain).The VBI value for each pixel is multiplied by this value, and the result is divided by
128.
VBI_SCALE_OFFSET (VBI Scale Offset). This field contains a signed number between −128 and +127. This value is
7:0
added to the VBI value of each pixel.
358
Video Processor Module - Video Processor Registers - Function 4
DAC Control Register
VBI Scaler Register
AMD Geode™ SC1200/SC1201 Processor Data Book
Reset Value: 00000020h
Reset Value: 00000004h