VTI Instruments EX1629, Руководство пользователя

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274 EX1629 Command Set
The dioLines parameter is an array of four elements with each array element being an unsigned 8-bit integer. Each
bit of this integer corresponds to a digital I/O channel. Specifically, the least significant bit corresponds to a digital
I/O channel zero, and the most significant bit corresponds to digital I/O channel seven. Each element specifies which
events the EX1629 will accept as trigger events on the digital I/O bus for different clock edges or states. If a user
wants to specify a channel for trigger events, the corresponding bit should be set to “1”. Specifically, the individual
array elements specify the following:
0 = dioLines[0] Positive Edge
1 = dioLines[1] Negative Edge
2 = dioLines[2] Positive Level 3 = dioLines[3] Negative Level
For example, if a user wishes to trigger the EX1629 on a negative edge signal coming into the digital I/O bus on
channels 0 and 3, then:
dioLines[1] = 00001001 = 0x09 = 9.
With regard to the
lxiOutput parameter, it is important to note that since the EX1629 can simultaneously accept
trigger events from multiple sources, it is necessary to reserve one of the LXI Trigger Bus line to communicate these
events within the device and to other devices in a multi-device configuration. If the EX1629 is a master driving
trigger events to peripheral slaves, the
lxiOutput parameter specifies the LXI Trigger Bus line that will be used to
communicate the trigger event to the slave devices. It is also necessary to configure this LXI Trigger Bus line to be
used as an output (see vtex1629_set_lxibus_configuration).
The
lxiInput parameter specifies which trigger bus line the master device uses for its trigger events. Although this
parameter is often set to the same value as lxiOutput , there are cases where it might be set to a different value. For
instance, when the device is configured as a master device in a star multi-box configuration, the master might output
the trigger event on LXI2 and input it back in on LXI6.
Decimal
Value
Hex
Value
#define Symbol
lxiOutput/lxiInput
Description
0 0x00 VTEX1629_LXI_LINE_ZERO LXI LINE 0
1 0x01 VTEX1629_LXI_LINE_ONE LXI LINE 1
2 0x02 VTEX1629_LXI_LINE_TWO LXI LINE 2
3 0x03 VTEX1629_LXI_LINE_THREE LXI LINE 3
4 0x04 VTEX1629_LXI_LINE_FOUR LXI LINE 4
5 0x05 VTEX1629_LXI_LINE_FIVE LXI LINE 5
6 0x06 VTEX1629_LXI_LINE_SIX LXI LINE 6
7 0x07 VTEX1629_LXI_LINE_SEVEN LXI LINE 7
8 0x08 VTEX1629_LXI_LINE_NONE None
E
XAMPLE
ViSession instrumentHandle;
ViStatus status;
ViInt16 triglines[VTEX1629_MAX_LINES];
ViInt16 diolines[VTEX1629_MAX_LINES];
…
triglines[0] = 0x00;
triglines[1] = 0x01;
triglines[2] = 0x48;
triglines[3] = 0x00;
diolines[0] = 0x0000;
diolines[1] = 0x0009;
diolines[2] = 0x0000;
diolines[3] = 0x0000;
status = vtex1629 vtex1629_set_pattern_trigger_configuration (instrumentHandle,
triglines,
diolines,
VI_FALSE,
VTEX1629_LXI_LINE_THREE,
VTEX1629_LXI_LINE_THREE);