Intel® FPGA Download Cable II User Guide

ID 683719
Date 5/13/2024
Document Table of Contents

3. TCK Frequency Auto-Adjust for Intel® FPGA Download Cable II

The TCK Frequency Auto-Adjust is a new feature implemented in Quartus® Prime 19.1 Pro release for the Intel® FPGA Download Cable II . This feature provide convenience and prevents incorrect TCK frequency setting that might cause slower device failure during JTAG operation.

The auto-adjust feature is enabled as default. To disable the auto-adjust feature, you can use the command line interface or Programmer GUI. The status of the feature is reset to default (enabled) when the cable is reconnected or JTAG server is restarted.

The auto-adjust feature always applies optimum frequency that can support on the current JTAG chain based on the BYPASS tests. If you specified a TCK frequency, the auto-adjust feature stops at the specified TCK frequency with the condition that the BYPASS tests are passing at the frequency.

Otherwise, the auto-adjust feature continues and will stop at lower frequency which the BYPASS tests are passing.

This new feature is only applicable when both Quartus® Prime and JTAG server are in version 19.1. If you use Quartus® Prime 19.1 with older JTAG server (before version 19.1), the auto-adjust feature is not available.

Note: The TCK frequency auto-adjust is designed based on the hard JTAG scan chain. For virtual JTAG scan chain, the TCK frequency after auto-adjust may still require further adjustment from the user for successful JTAG operation.