Assuming a standard connector is used for UX2, the pinout select switch component could be placed adjacent to it in such a way that, if a cable is present in the connector, the switch will be inaccessible.

This would ensure that cable must be removed prior to changing pinout, reducing chances of fried circuits.

The power select switch (see: #1), if implemented, would benefit from same approach.

Note: Ensure that putting in the cable doesn't risk accidental alteration of switch settings.

Separating out from #1 in to dedicated issue to track.

Addition of a power select switch could potentially facilitate, in combination with pin variant switches, additional modes for the MCU and UX2 bus:

• Reset MCU
• Program MCU
• Custom Bus Mode

This would facilitate custom updates to MCU and bus function, making it much more useful to makers.

SMBus operates at lower voltage (2.1V) compared to I2C (3.3V). Rotary switch to select voltage could be useful in this instance.

Furthermore, in combination with pinout select switches, could possibly be used to provide alternate modes for the bus. Specifically, depending on accuracy of GPIO that monitors the pin variant switches, the voltage select could provide a bunch of extra modes.

Example: If the power select had 3 states (1, 2, 3):

1. Custom bus mode / program mode
2. 2.1V
3. 3.3V

With power select set to 1, the MCU could enter a programmable state allowing end-user to completely reconfigure the UX2 bus to their own needs. For example, a bus consisting primarily of GPIO with custom code running on the MCU to translate between it and master MCU.