• Zach Pfeffer

Change the Boot Mode of the Xilinx Zynq UltraScale+ MPSoC from XSCT


This post show you how to change the boot mode of the Zynq UltraScale+ MPSoC from XSCT.

TL;DR

The following sequence changes to JTAG boot mode:

Thanks!

Big thanks to Krishna Chaitanya (LinkedIn) for sharing this awesome method!

Motivation

Being able to change the boot mode remotely helps debug. Typically, the user will change boot from from whatever it is to JTAG Boot to load a custom build.

By writing the new boot mode to BOOT_MODE_USER (CRL_APB) Register @ 0xff5e0200 and triggering a software reset, the MPSoC will use the mode you wrote, not the mode of the strapping pins.

Sequences

Here are sequences for each boot mode:

JTAG

Quad-SPI (24b)

Quad-SPI (32b)

SD0 (2.0)

NAND

SD1 (2.0)

eMMC (1.8V)

USB (2.0)

PJTAG (MIO #0)

PJTAG (MIO #1)

SD1 LS (3.0)

References

  • Zynq UltraScale+ MPSoC Register Reference @ link

  • CSS Tables @ link

Boot Modes

Table is available here as an Excel.

0xff5e0200 Documentation

BOOT_MODE_USER (CRL_APB) Register

Description

BOOT_MODE_USER (CRL_APB) Register Bit-Field Summary

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