The Versal families MIO and HDIO banks can be powered at 2.5V or 3.3V. When using a tristate control at 3.3V and 2.5V drivers, a race condition can exist between data and the tristate control that could result in an incorrect output value.
There is a minimum skew requirement for the Data and T (tristate) signals as shown in Figure 1.
Figure 1: Tristate/Data transitions that can lead to the race condition
The following use cases might involve the use of tristate with 3.3V and 2.5V:
- HDIO – OBUFT, IOBUFT
- Sysmon I2C/PMBus usage
- MIO SelectMAP Interfaces
- MIO USB2.0 Interfaces
- JTAG TDO
- JTAG HDIO EXTEST and JTAG MIO EXTEST
- GTS assertion
- SRST assertion
Note: not all device/package combinations have HDIO banks.