Chapter 3
Hardware Overview
PCI-MIO E Series User Manual
3-18
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National Instruments Corporation
Board and RTSI Clocks
Many functions performed by the PCI-MIO E Series boards 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.
A PCI-MIO E Series board can use either its internal 20 MHz timebase
or a timebase received over the RTSI bus. In addition, if you configure
the board to use the internal timebase, you can also program the board
to drive its internal timebase over the RTSI bus to another board that is
programmed to receive this timebase signal. This clock source, whether
local or from the RTSI bus, is used directly by the board 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.
RTSI Triggers
The seven RTSI trigger lines on the RTSI bus provide a very flexible
interconnection scheme for any PCI-MIO E Series board sharing the
RTSI bus. These bidirectional lines can drive any of eight timing
signals onto the RTSI bus and can receive any of these timing signals.
This signal connection scheme is shown in Figure 3-12.
