AR# 53615 Zynq-7000 AP SoC ZC702 Evaluation Kit - INIT LED unexpectedly goes red
Description
Some ZC702 Rev 1.0 boards could exhibit an issue related the Digilent USB-JTAG SMT1 modules whichmanifests itself in two ways:
1.DS2 INIT LED unexpectedly illuminates red, or
2.Zynq-7000 Z7020 device or ARM processoris un-detectableinthe JTAG chain
Solution
A footprint incompatibility between the Digilent USB JTAGSMT1 and SMT2 modules may result in unexpected behavior on ZC702 boards withserial numbersbeginning with 1224-xxxx.
This can result in failure to detect the ARM processor in the JTAG chain and may cause the INIT LED to illuminate red and remain red as the ARM processor is held in reset.
ZC702 Rev 1.0boards whose serial number begin withS/N 1224-xxxx may be affected by this issue.
Following is a simple board modification to prevent this issue from occurring.
1. Locate U23, Digilent SMT1 USB-JTAG module, on top side of board.U23 is located near Mounting Hole MH6.
2. Next, you will cut a trace between the U23-11 PAD and neighboring Via (cut per Red line marking) with an X-ACTObladeor similar device, as shown below:
zc702_u23_mod.jpg
Linked Answer Records
Master Answer Records
| Answer Number | Answer Title | Version Found | Version Resolved |
|---|---|---|---|
| 47864 | Zynq-7000 AP SoC ZC702 Evaluation Kit - Known Issues and Release Notes Master Answer Record | N/A | N/A |