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4.7
IVI AND M-MODULE DRIVERS
An IVI Instrument Driver is available for status and control of the EM405-8 carrier. The driver
provides full control of carrier functions, such as configuring the trigger logic, reading the
temperature sensors, controlling the fans, and reading and writing registers on the M-Modules.
M-Modules themselves may also have a device driver that can be used to directly control the
various functions of the M-Module. Since the M-Modules contain the primary functionality of
the integrated unit, in many cases, the M-Module driver will be used exclusively. Contact the
particular M-Module manufacturer for documentation and details on an M-Module driver.
4.8
CONTROLLING THE TRIGGERS
The EM405-8 carrier (-0001 version only) implements flexible trigger control capabilities
providing the user with many options for using triggers. Although not all M-Modules support
triggers, each M-Module position on the EM405-8 carrier can support both of the possible
trigger lines (TRIGA & TRIGB) on an M-Module. The function of each M-Module trigger line
is fully dependent upon the M-Module. Refer to the particular M-Module’s documentation for
details. The carrier also provides external TTL level trigger access through two external BNC
connectors and LVDS level triggers through double stacked micro-D connectors
Each trigger can be configured to be either an input or output.
The direction is always
referenced with respect to the internal trigger control logic.
For example, a trigger produced
by an M-Module is referred to as an
input
trigger, because the trigger is an input to the internal
trigger control logic. A trigger received by an M-Module is referred to as an
output
trigger,
since it is produced by the internal trigger logic. If the trigger is defined as an input, then it can
be used to produce a trigger to an M-Module or an external device. A single input trigger can be
used to drive any number of output triggers. If a trigger is defined as an output then the source
of the trigger must be specified.
The internal trigger logic provides input conditioning and routing of the trigger signals as shown
in Figure 12. Each trigger type (Trig A and B for each M-Module, LVDS Triggers 0-7, or
External TTL level) can be simply passed-through (level triggering) or latched on the rising or
falling edge (edge triggering) of another signal (EDGECLK). Up to four EDGECLK’s can be
specified. An EDGECLK can any signal specified as an input. Optionally, the input signal can
be inverted. Any signal defined as an input can be used as an output trigger. In addition, the
output trigger can be inverted as shown in Figure 13.
TTL level triggering is provided through two external BNC connectors. One connector is for an
input trigger and the other is for an output trigger. The TTL input trigger has a software
configurable threshold and input impedance. The input threshold is configurable using the
TLVL bit in the
TTL Trigger Control
register and can be set to 1.4 volts or +2.5 volts.
The input impedance is configurable using the TIMP bit in the
TTL Trigger Control
register and
can be set to either high impedance (>900K
or 50
. The output trigger line has a set output
impedance of 50
and a set output drive level of +5V (typical) into a high impedance load.
C&H Technologies, Inc. <> 445 Round Rock West Drive <> Round Rock, Texas 78681 <> www.chtech.com
