diff --git a/hardware/keyboardio/cores/keyboardio/USBCore.cpp b/hardware/keyboardio/cores/keyboardio/USBCore.cpp
index 22b816e6..113926e3 100644
--- a/hardware/keyboardio/cores/keyboardio/USBCore.cpp
+++ b/hardware/keyboardio/cores/keyboardio/USBCore.cpp
@@ -656,6 +656,8 @@ static inline void USB_ClockEnable()
 #else
 #error "Clock rate of F_CPU not supported"
 #endif
+#else
+#error "USB Chip not supported, please defined method of USB PLL initialization"
 #endif
 
 	PLLCSR |= (1<<PLLE);