34 Chapter 5: Hardware reference
• Edge-triggered monoshot acquisition: The VIA (Video Interface ASIC) waits for
the rising/falling edge to capture a single frame.
• Edge-triggered continuous acquisition: The VIA waits for the rising/falling edge
to start a continous grab.
• Level-sensitive "continuous" acquisition: The VIA grabs continuously while the
level of the trigger is high/low.
!The polarity of the active and inactive levels of the trigger signal is software
programmable.
Matrox Meteor-II /Camera Link can also operate in asynchronous reset mode. In
this mode, the digitizer resets the camera to begin a new frame when the trigger
signal is received.
Data interfaces
Video Interface ASIC
The Matrox Meteor-II /Camera Link board has a VIA, which acts mainly as a
video-to-PCI bridge. The VIA is capable of high-speed image transfers to Host
memory or other PCI devices across the PCI bus. It uses 32Mbytes of video
transfer memory (SDRAM) to store data until the PCI bus becomes available. On
the PCI form factor, the VIA also supports image transfers across the VMChannel
to on e o r m ore Ma tr ox I ma gin g b oa rds fo r accelerated image processing or display.
Simultaneous data
streams
Matrox VIA can manage up to two simultaneous data streams. For example, it
can grab into video transfer memory, and concurrently transfer data over the
VMChannel (for PCI form factor only) or PCI buses.
General features The VIA is capable of separating image data into two, three, or four 8-bit or two
16-bit components (for example, RGB packed to RGB planar). This mechanism
is also used to merge line segments of monochrome multi-tap cameras.