-LUFA_OPTS = -DUSB_DEVICE_ONLY
-LUFA_OPTS += -DUSE_FLASH_DESCRIPTORS
-LUFA_OPTS += -DUSE_STATIC_OPTIONS="(USB_DEVICE_OPT_FULLSPEED | USB_OPT_REG_ENABLED | USB_OPT_AUTO_PLL)"
-#LUFA_OPTS += -DINTERRUPT_CONTROL_ENDPOINT
-LUFA_OPTS += -DFIXED_CONTROL_ENDPOINT_SIZE=8
-LUFA_OPTS += -DFIXED_NUM_CONFIGURATIONS=1
+TMK_LUFA_OPTS = -DUSB_DEVICE_ONLY
+TMK_LUFA_OPTS += -DUSE_FLASH_DESCRIPTORS
+TMK_LUFA_OPTS += -DUSE_STATIC_OPTIONS="(USB_DEVICE_OPT_FULLSPEED | USB_OPT_REG_ENABLED | USB_OPT_AUTO_PLL)"
+# Do not enable INTERRUPT_CONTROL_ENDPOINT for converters which requires ISR in particular,
+# it can block other ISRs long like 500-1000us for HID keyboard LED report.
+#TMK_LUFA_OPTS += -DINTERRUPT_CONTROL_ENDPOINT
+TMK_LUFA_OPTS += -DFIXED_CONTROL_ENDPOINT_SIZE=8
+TMK_LUFA_OPTS += -DFIXED_NUM_CONFIGURATIONS=1