Data I/O UniSite-xpi, User Manual

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4. Commands
UniSite-xpi User Manual 4-31
• Serial Vector Test (Y,N)—When enabled, this test applies each
vector’s input states serially, starting with pin one and stepping
through the remaining pins. This test is a diagnostic tool designed to
help debug and classify test vector failures. Specifically, this test is
designed to isolate test vectors that are sequence dependent. If a
sequence-dependent vector is found, it should be broken into two or
more vectors to make them sequence independent.
The JEDEC specification for test vectors requires that test vectors be
sequence independent. If sequencing between pins is important, then
the test vector should be separated into two or more vectors to make
them sequence independent. This test helps isolate vectors that are
sequence-dependent and that should be expanded.
This switch is available only for logic devices and is disabled on
power up. The switch is also returned to N when parameters are
restored or when another device is selected.
• High Speed Logic Drivers (Y,N)—When enabled, this feature
increases the speed of the logic transitions between 0 to 1 and 1 to 0 of
the test vector input states.
The speed of the logic transitions is increased by driving the 0 and 1
levels using the high speed logic drivers instead of a current limited
driver.
The JEDEC specification for test vector 0 and 1 input states defines
that these inputs be current limited, so that the outputs of the device
under test can overdrive the 0 or 1 level. However, current-limited
drivers have inherently slow transition speeds. Enabling this feature
reduces the possibility of doubling clocking due to slow transition
times.
This switch is available only for logic devices. It defaults to Y on
power up and stays on until turned off.
CAUTION: If used with invalid test vectors that drive outputs, the High
Speed Logic Drivers test may cause over current errors.
• Compensated Vector Test (Y,N)—Y enables load compensation on
PLD output pins under test during vector testing. This may eliminate
structured test errors when testing PLDs sensitive to output loading,
where many of the device’s registers transition simultaneously. This
test is available only for logic devices and defaults to N at power up.
This parameter defaults to Y if you select a non Open Collector
device, and defaults to N if you select an Open Collector device. This
parameter can be saved/restored with the Save/Restore
Configuration command.
• Display Device Footnote (Y,N)—When enabled, this feature enables
the automatic display of device specific information (if any is
available for the selected device).
• Abort on Empty Socket (Y,N)—When this option is enabled, all
device operations will automatically be aborted on empty sockets.