User manual

Chapter 3 Hardware Overview
NI 6034E/6035E/6036E User Manual 3-6 ni.com
Figure 3-2 shows that CONVERT* can be generated from a number
of sources, including the external signals RTSI<0..6> and PFI<0..9> and
the internal signals Sample Interval Counter TC and GPCTR0_OUT.
Many of these timing signals are also available as outputs on the RTSI pins,
as indicated in the RTSI Triggers section in this chapter, and on the PFI
pins, as indicated in Chapter 4, Connecting Signals.
Programmable Function Inputs
The 10 PFI pins are connected to the signal routing multiplexer for each
timing signal, and software can select any one of the PFI pins as the
external source for a given timing signal. It is important to note that any
of the PFI pins can be used as an input by any of the timing signals and that
multiple timing signals can use the same PFI simultaneously. This flexible
routing scheme reduces the need to change physical connections to the I/O
connector for different applications.
To use the PFI pins as outputs, you must use the Route Signal VI to
individually enable each of the PFI pins to output a specific internal timing
signal. For example, if you need the UPDATE* signal as an output on the
I/O connector, software must turn on the output driver for the
PFI5/UPDATE* pin.
Device and RTSI Clocks
Many functions performed by the NI 6034E/6035E/6036E require
a frequency timebase to generate the necessary timing signals for
controlling A/D conversions, DAC updates, or general-purpose signals
at the I/O connector.
The NI 6034E/6035E/6036E device can use either its internal 20 MHz
timebase or a timebase received over the RTSI bus. In addition, if you
configure the device to use the internal timebase, you can also program the
device to drive its internal timebase over the RTSI bus to another device that
is programmed to receive this timebase signal. This clock source, whether
local or from the RTSI bus, is used directly by the device as the primary
frequency source. The default configuration at startup is to use the internal
timebase without driving the RTSI bus timebase signal. This timebase is
software selectable.
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