NI-Digital Pattern Driver 17.1, 17.1.1, and 17.5 Skew Bug Fixes
Updated Mar 17, 2020
An issue has been identified in the NI-Digital Pattern Driver for versions 17.1, 17.1.1, and 17.5 which may result in inconsistent skew between synchronized PXIe-6570 digital pattern instruments. Please review the information below to understand the issue, determine if you are affected, and evaluate the actions that are available to you for correcting and preventing this issue.
In version 17.1 of the NI-Digital Pattern Driver, a new feature called Timing Absolute Delay was introduced which allowed the optional reduction of instrument-to-instrument skew when synchronizing multiple digital pattern instruments outside of an NI Semicoductor Test System*. Due to a bug in the driver, if multiple digital pattern instruments are synchronized and the Timing Absolute Delay property is not enabled, an additional instrument-to-instrument skew of 10 ns will appear inconsistently from one test execution to the next. The manifestation of this bug may not be readily apparent, but can result in intermittent test failures due to misaligned instrument I/O. This issue is not present when Timing Absolute Delay is enabled.
To be affected by this issue, a test system must meet the following conditions:
1. Using NI-Digital Pattern Driver version 17.1, 17.1.1, or 17.5
2. Using multiple PXIe-6570 digital pattern instruments in the same PXI chassis
3. Using the NI-TClk API to synchronize multiple digital pattern instruments, independent of the programming language used.
4. Not setting the Timing Absolute Delay property to Enabled (the default value is Disabled)
NI Semiconductor Test Systems (STS) use preconfigured software bundles which never included versions 17.1, 17.1.1, or 17.5 of the NI-Digital Pattern Driver. However, if the system has been manually upgraded to 17.1, 17.1.1, or 17.5 users should evaluate the above conditions to determine if their system is affected by this issue.
If your test system meets the conditions above, please take at least one of the following actions:
a) Upgrade your NI-Digital Pattern Driver to version 18.0 or above. This issue has been corrected in version 18.0.
b) If you’re not using an NI Semiconductor Test System (STS), set the Timing Absolute Delay property to Enabled in your test program*. This will prevent the issue from appearing and provide consistent, reduced skew between digital pattern instruments. Note that without upgrading your NI-Digital Pattern Driver, it will still be possible to overlook this requirement in the future and allow the issue to appear.
*Semiconductor Test System customers should never enable Timing Absolute Delay. Timing Absolute Delay conflicts with the adjustment performed during STS timing calibration.
Customers who are not presently affected by this issue do not need to take any action. However, it is recommended to use version 18.0 or later of the NI-Digital Pattern Driver to avoid the conditions in which the issue can appear.