Why can’t I find guidance on how to access the SDC cookbook for JTAG signal constraints from the Download Cable II User Guide?

Description

In the Download Cable II User Guide, Section 2.7: JTAG Timing Constraints and Waveforms, there is no guidance on how to access the SDC Cookbook for JTAG signal constraints.

This may lead to confusion for users who need to apply timing constraints correctly when using the Download Cable II.

Resolution

Follow these steps to add the JTAG signal constraints template from the SDC Cookbook:

1. Navigate to File > New > SDC File, then click OK.
2. In the newly opened SDC file, right-click and select Insert Template.
3. In the Insert Template window, go to:
   • Timing Analyzer > SDC Cookbook > JTAG Signal Constraints

Include the following note to clarify usage:

• Users may adjust the Download Cable II (USB Blaster II) cable length to match their design.
• Do not modify the USB Blaster parameters listed below, as they are critical for proper operation:

  1. set tck_blaster_tco_max 14.603

  2. set tck_blaster_tco_min 14.603

  3. set tms_blaster_tco_max 9.468

  4. set tms_blaster_tco_min 9.468

  5. set tdi_blaster_tco_max 8.551

  6. set tdi_blaster_tco_min 8.551

  7. set tdo_blaster_tsu  5.831

  8. set tdo_blaster_th -1.651

Related Articles

2.7. JTAG Timing Constraints and Waveforms