* **board** - breakout-specific pin identities
* **microcontroller** - chip-specific pin identities
+* **analogio** - analog input/output pins, using pin identities from board+microcontroller packages
* **digitalio** - digital input/output pins, using pin identities from board+microcontroller packages
* **bitbangio** - software-driven interfaces for I2C, SPI
* **busio** - hardware-driven interfaces for I2C, SPI, UART