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<@U016EM8L91B> 
Hi Tim,
Quick question: Can the vccd1 and vccd2 support 3.3V in particular the HV standard cells?

No.  The `vccd` domains are limited to 1.8V.  Use the `vdda` domains for 3.3V+ voltage.

<@U016EM8L91B> 
So the vdda can support the digital standard cell?

If you use a 3.3V (up to 5.5V) voltage domain, you can synthesize to the `sky130_fd_sc_hvl` library, which supports that supply voltage.

Note, however, that outputs to the GPIO and the SoC are all on 1.8V, so you would need to use the level-shift-down cells from `sky130_fd_sc_hvl` to connect to those.  There is a 3.3V-level input from the GPIOs, though, that you can use directly as input to a 3.3V circuit.