Unlisted GPIO

Hi Guys,

My hardware designers (bless em) have used a GPIO pin (GPIO_9_USB_SEL) as a relay output. This pin isn’t mentioned in the I/O list (A-Z, etc), but I notice there are gaps in the list. Does this pin have a designator or do I need to re-route it.

Many thanks


Is this imp005? You’ll need to re-route it, sorry: that pin’s not accessible from Squirrel.


We did a lot of iteration on which pins were highest value on imp005; we do recommend that, if possible, you use our schematic symbol in your designs as this then prevents such issues.

We only have footprints for Altium right now, though. What CAD package do your designers use? Possibly we should widen the footprint availability a bit to include Eagle etc.

Eagle would be nice :slight_smile:

Sorry, yes this is an imp005, we do use Altium so that will be a great help. Many thanks

If you use altium then the symbol is in the imp005-breakout altium files, available here:


Thanks Hugo