I am actively interested in purchasing this eval board, both for access to a ZU1CG along with SYZYGY compatibility with modules I am working on.
On the SYZYGY's group webpage as of Feb/18/2023 (https://syzygyfpga.io/carriers/), the ZUBoard 1CG has a note next to it stating:
" IMPORTANT: This product IS NOT SYZYGY Compliant. "
Can AVNET provide any insight into this, seeing as functionality with this ecosystem is a large selling point for this product and the trademark is used in the product description and marketing material? My take away is peripherals will work assuming the end user makes SURE that the voltages are compatible before plugging them in.
From what I have been able to ascertain, the compliance issue stems from the lack of "SmartVIO" support, see 4.2.1 VIO Supply in the SYZYGY specifications V1.1. The spec seems to require that the VIO that is provided to the SYZYGY peripherals be adjustable on the carrier side to match what is needed by the peripherals if required. The ZUBoard seems to just hook a voltage rail to the VIO pin 39, and provide a fixed voltage, 1.8 V to port A, and 1.2 V or 1.8 V to ports B and C, where these are required to be independent adjustable supplies.
Additionally, the spec requires that the VIO rails be the last supply provided to the peripherals in the start up sequence. This was likely done to ensure that too high a voltage was never given to a device. Section 4.3 of the specifications outlines this.
I looks like adding 3x adjustable fs1406's to the board near the SYZYGY ports and connecting them to the same i2c bus could allow the SYZYGY state machine to control the VIO supplies and seemingly obtain SYZYGY compliance.
Also, feedback on the schematics. Consider adding notes for expected current draw on different rails, Vdiv notes for fixed supplies, voltage drop information near beads and any high current planes, and beads to help keep noise out of different areas when one rails is feeding many different functional blocks (see power supply page).