Cyclone® V Device Handbook: Volume 1: Device Interfaces and Integration

ID 683375
Date 10/18/2023
Document Table of Contents

9.1.3. JTAG Secure Mode

If you enable the tamper-protection bit, the Cyclone® V device is in JTAG secure mode after power up. In the JTAG secure mode, the JTAG pins support only the BYPASS, SAMPLE/PRELOAD , EXTEST, IDCODE, SHIFT_EDERROR_REG , and UNLOCK instructions. Issue the UNLOCK JTAG instruction to enable support for other JTAG instructions.