worked around a dumb errata
diff --git a/gyro_board/src/usb/CAN.h b/gyro_board/src/usb/CAN.h
index 1ef39d5..60f2d10 100644
--- a/gyro_board/src/usb/CAN.h
+++ b/gyro_board/src/usb/CAN.h
@@ -14,6 +14,9 @@
 } can_message;
 
 int CAN_get(can_message *message);
+
+// Sets up PCLKSEL for CAN stuff (errata PCLKSELx.1).
+void CAN_PCLKSEL(void);
 void initCAN(void);
 
 #endif