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VM1548C Programming
27
B
I
-
DIRECTIONAL
C
LOCK
C
IRCUIT
There are six independent bi-directional clock circuits connected to the 68-pin external connector.
Each clock is associated with one of the 6 ports previously described. Therefore, <port #>
terminology is used to refer to a specific clock. When the circuit is configured as an output, the
clock signal will be sourced by the module. When the circuit is configured as an input, the clock
signal is sourced by the UUT. This clock (CLK0-5) may be used for many different purposes: a
trigger source; selections for the interrupt trigger; a port’s input clock; a port’s output clock.
The following SCPI command configures the clock line as an output:
OUTPut:CLOCk:ENABle ON
The following SCPI command configures the clock line as an input:
OUTPut:CLOCk:ENABle OFF
When the circuit is operating as an output, the clock source is selectable using the following SCPI
command.
OUTPut:CLOCk:SOURce <port #> <source>
Where <source> is TTLTRIG,
IMMEDIATE, GLOBAL
(TRIGOUT) or NONE
The polarity of the output clock signal is controlled with the following SCPI command.
OUTPut:CLOCk:POLarity <edge>
Where <edge> is NORMAL or
INVERT
EXAMPLES
To drive TRIGIN out as CLK1 on the external connector, the following SCPI commands would
be issued.
OUTPut:CLOCk:ENABle 1 ON
OUTPut:CLOCk:SOURce TTLTRIG
To drive TRIGOUT out as CLK3 on the external connector, the following SCPI commands would
be issued:
OUTPut:CLOCk:ENABle 3 ON
OUTPut:CLOCk:SOURce GLOBAL
To drive IMMEDIATE out as CLK5 on the external connector, the following SCPI commands
would be issued:
OUTPut:CLOCk:ENABle 5 ON
OUTPut:CLOCk:SOURce IMMEDIATE
To select no clock, the NONE parameter is used. This will always be a logic level low.
OUTPut:CLOCk:ENABle 5 ON
OUTPut:CLOCk:SOURce NONE
