402-00005-00
DAC and PLL Programming
4–16
Rev 02; February 8, 2002
PLLA6 = 0x44[0xxx] (where xxx = LCOUNT bits, from value found in tables)
LCOUNT = use bit definition for the value found in tables.
OMUX1 = 0 (use default)
EXTREF = 1 (external reference Input operation)
6.
Calculate Window Generator Horizontal settings as follows:
HACTIVE = [total # of pixels from hsync to end of the active region] – 2
= ( Hsync + Back Porch – Crop-End) – 2
HOFF = [Total # of pixels from Hsync to the start of active video]
= (Hsync + Back Porch + Crop-start)
Use the following formulas to determine the number of pixels in each region of the HACTIVE/HOFF formulas:
Active = Active time / Pclk (in us)
Hsync = HSync Time / Pclk (in us)
Back Porch = Back Porch Time / Pclk (in us)
Crop-End = Number of pixels to Crop from the end of active video region
Crop-Start = Number of pixel to Crop from start of active video region
For RS-170: Active = 52.656 us Hsync = 4.7 us Back Porch = 4.7 us
For CCIR: Active = 51.95 us Hsync = 4.7 us Back Porch = 5.8 us
NOTE
The Active region must be divisible by 8.
NOTE
Any change to HOFF will shrink or expand the number of active pixels loaded in the horizontal
direction. You must maintain the x4 restriction. Changes to HOFF must be accounted for in HAC-
TIVE.
7.
Set the Window Generator Vertical settings as follows:
VACTIVE = [# of lines from Vsync to the end of Active video ] – 1
= (V Vsync + Vblank – Vcrop-End) – 1
VOFF = [# of lines from Vsync to the start of Active video ] – 1
= (Vsync + Vcrop-Start) – 1
Vactive = # of lines per field/frame
Vsync = # of lines in Vsync
Vblank = # of lines from Vsync to the start of active video
Crop-End = # of lines to Crop from the end of active video region
Crop-Start = # of lines to Crop from start of active video region
For RS-170:
Total Lines per Frame = 525
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