AR# 57930

Design Advisory for Zynq-7000 SoC - Boundary Scan test fails when VMODE is set to 1.8V

Description

Boundary Scan tests for PS MIO inputs may fail on Zynq-7000 devices when the PS MIO banks VMODE is set to 1.8V and VCCO is connected to a 1.8V supply.

Designs Affected

Any Zynq-7000 device attempting to perform a Boundary Scan EXTEST command when VMODE[1:0] is set to 1.8V with a VCCO of 1.8V. 

A VMODE[1:0] of 1.8V corresponds to a MIO[8:7] setting that does not equal 00.

Typically, boundary tests are used during pre-production or production board tests.

Solution

Work-around

While running Boundary Scan EXTEST commands, VMODE must have been set to 2.5V/3.3V at power-on/reset, even if using a 1.8V VCCO voltage. 

Operating the I/Os at 2.5V/3.3V is safe and will not damage the I/Os during operation when VCCO is set to 1.8V.

A jumper or other ability to change the VMODE setting is required on the board if Boundary Scan tests are desired with a 1.8V MIO VCCO voltage.

The Zynq-7000 Technical Reference Guide (UG585) will be updated starting in version 1.8.

AR# 57930
Date 05/21/2018
Status Active
Type Design Advisory
Devices