Article Details

ID: 606
Case Type: faq
Category: Device Programming
Related To: ispVM System
Family: All Devices

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What could cause the \u201CJTAG-NOP\u201D error message in ispVM System tool?

"JTAP-NOP" indicates that a device was detected, but its JTAG IDCODE is not in the ispVM System database. There are a few reasons this may occur:

  1. The device is a newer Lattice device and is not yet supported by the version of ispVM System that you are using. Installing the latest version of ispVM System will provide the most recent device database.

  2. The Lattice device was not added to the database when ispVM System was installed. To add more devices, use the Device Database Installation wizard in ispVM System, found under the Options menu.

  3. The device is from another vendor. Non-Lattice devices can exist in the chain and be bypassed. The instruction register length of these devices must be specified. The user can either enter a known value for the device manually, or import the BSDL file available from the manufacturer.

  4. The JTAG IDCODE of devices in the chain were misread due to signal quality problems. False edges on TCK or voltage incompatibilities are examples of issues that may cause this. The ispDOWNLOAD cable should also be connected to an appropriate power supply and stable ground reference to ensure proper generation and detection of the JTAG signals.
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