402-00005-00
Registers
3–46
Rev 02; February 8, 2002
3.4.7.6 VSCAN Clock Input Select (VSCLKSEL) R/W
In variable scan mode, the clock can be input on the CLKIN0 and CLKIN1 pins, or on the FRESET0 and FRESET1
pins. This added flexability allows support for some of the camera adapter cables developed for the earlier PCVision
frame grabber.
VSCLKSEL
Function
0
Clock input on CLKIN inputs
1
Clock input on FRESET inputs
3.4.7.7 Oversample Input Mode Select (OVRSM) R/W
The OVRSM bit defines the data input to the Input LUT as one 12-bit pixel from the ADC with four static page select
bits, or two 8-bit pixels, odd and even, made from 12-bit data with the 4 lsbs (least significant bits) truncated. To
perform oversampling, program the pixel clock to twice the normal sample rate and program the Input LUT to aver-
age the two adjacent pixel values.
OVRSM
Function
0
Normal mode: 12-bit pixels and 4 page bits
1
Oversample mode: two 8-bit odd and even pixels
3.4.7.8 Variable Scan Clock Input Polarity Select (VCLKPOL) R/W
The VCLKPOL bit can invert the incoming variable scan clock when PCVisionplus is in variable scan mode. Inter-
nal circuits sample the video signal on the rising edge of the clock. If your camera uses a falling edge clock, enable the
invert.
VCLKPOL
Function
0
Disable invert (do not invert clock input)
1
Enable invert (invert the clock input)
3.4.7.9 Line Enable Input Polarity Select (LENPOL) R/W
This bit selects which edge of the LEN input enables the PWG horizontal counter, starting horizontal window gener-
ation. Program this bit to zero for XTAL and PLL modes. Only use this bit to invert the LEN input for VSCAN
modes.
LENPOL Function
0
Falling edge enables horizontal timing
1
Rising edge enables horizontal timing
3.4.7.10 Frame Enable Input Polarity Select (FENPOL) R/W
The FENPOL bit selects which edge of the FEN input enables the PWG vertical counter, starting vertical window
generation. Program this bit to zero for XTAL and PLL modes. Only use this bit to invert the FEN input for VSCAN
modes.
FENPOL Function
0
Falling edge enables vertical timing
1
Rising edge enables vertical timing
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com