National Instruments PXI-1428 - Manual (Page 23)

Chapter 3 Hardware Overview
IMAQ PCI/PXI-1428 User Manual 3-4 ni.com
High-Speed Timing
Built from high-speed counters, the high-speed timing circuitry on the
IMAQ 1428 can generate precise real-time control signals for your camera.
Map the output of this circuitry to a trigger line to provide accurate pulses
and pulse trains. Use these control signals to control exposure time and
frame rate.
Note For your convenience, the external control for cameras that support the IMAQ 1428
has been preprogrammed into the camera file. You can use MAX to specify the frequency
and duration of these signals in easy-to-use units.
Acquisition and Region of Interest (ROI)
The acquisition and ROI circuitry monitors incoming video signals and
routes the active pixels to the multiple-tap data formatter and SDRAM.
The IMAQ 1428 can perform ROI on all video lines and frames. In an ROI
acquisition, select an area within the acquisition window to transfer across
the PCI bus to system memory.
Note You can use MAX to set the acquisition and ROI parameters.
Scatter-Gather DMA Controllers
The IMAQ 1428 uses three independent onboard direct memory access
(DMA) controllers. The DMA controllers transfer data between the
onboard SDRAM memory buffers and the PCI bus. Each of these
controllers supports scatter-gather DMA, which allows the DMA controller
to reconfigure on-the-fly. The IMAQ 1428 can perform continuous image
transfers directly to either contiguous or fragmented memory buffers.
Bus Master PCI Interface
The IMAQ 1428 implements the PCI interface with a National Instruments
custom application-specific integrated circuit (ASIC), the PCI MITE.
The PCI interface can transfer data at a theoretical maximum rate of
133 MB/s in bus master mode.