+feather_m0 = { version = "0.9.0", features = ["usb"] }
+cortex-m = "0.6"
+embedded-hal = "0.2.3"
+cortex-m-rt = { version = "0.6.12", optional = true }
+atsamd-hal = "0.12"
+panic-halt = { version = "0.2", optional = true }
+usb-device = { version = "0.2", optional = true }
+usbd-serial = { version = "0.1", optional = true }