Chapter 2
Hardware Overview
2-4
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Multiple-Tap Data Formatter
Many digital cameras transfer multiple taps, or channels, of data
simultaneously to increase the frame rate of the camera. However, the data
in each tap may not be transferred in the traditional top-left to bottom-right
direction. Also, the taps may not transfer data in the same direction.
The multiple-tap data formatting circuitry on the NI 1426 can reorder the
data from up to three taps. The data from each tap can be independently
scanned either from left-to-right or right-to-left and top-to-bottom or
bottom-to-top.
Note
For your convenience, data reformatting instructions for these cameras have been
preprogrammed into the camera files.
SDRAM
Depending on the memory option purchased, the NI 1426 has 16 MB or
32 MB of onboard high-speed synchronous dynamic RAM (SDRAM). The
NI 1426 uses the onboard RAM as a FIFO buffer to ensure a complete
acquisition. Even when the data rate from the camera exceeds PCI
throughput, you can acquire without interruption until the onboard RAM
is full.
Trigger Control and Mapping Circuitry
The trigger control and mapping circuitry routes, monitors, and drives
the external and RTSI bus trigger lines. You can configure each line to start
an acquisition on a rising or falling edge and drive each line asserted or
unasserted, much like a digital I/O line. You also can map pulses from the
high-speed timing circuitry or many of the NI 1426 status signals to these
trigger lines. Four RTSI bus triggers and four external triggers (all of
which are programmable for polarity and direction) are available for
simultaneous use.
Individually configure the four external triggers in Measurement and
Automation Explorer (MAX), the National Instruments Configuration
utility, as single-ended I/O lines or, alternatively, as isolated or RS-422
input only lines. You can configure the four external triggers in any
combination of single-ended I/O or input only lines. Table 2-1 lists the
configuration options available for each trigger source.
