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Hi everyone, is there any technical documentation for the spec of the caravel GPIOs pads? We are assuming they are all level shifted up to 3.3v, is that correct? It would be nice for the future to simultaneously have 1.8v and 3.3v pads. It looks like the pad itself is capable of doing this from the skywater spice model, is this true? Is there a spec on the output (how many miliamps it can drive etc)?

All of the information about the I/Os can be found here:  <https://skywater-pdk.readthedocs.io/en/main/contents/libraries/sky130_fd_io/docs/user_guide.html>  (for SkyWater;  the GF documentation is elsewhere).

But the short answer is that yes, all pad-connected signals are 1.8V on the core side and 3.3V on the pad side, with level shifters in between.  There _is_ a 3.3V core side signal *in_h* which is just the signal *in* tapped before the level shifter.  There is no equivalent 3.3V core-side output.

Thank you :slightly_smiling_face: I found this while digging around too, putting it here incase it helps anyone else: <https://caravel-harness.readthedocs.io/en/latest/supplementary-figures.html>