diff --git a/src/Makefile b/src/Makefile
index 4b7050b..e69d2d4 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -64,7 +64,6 @@ SRC =			\
 	target.c	\
 	target_probe.c
 
-
 include $(PLATFORM_DIR)/Makefile.inc
 
 ifneq ($(PC_HOSTED),1)
@@ -91,10 +90,8 @@ endif
 ifdef PC_HOSTED
 CFLAGS += -DPC_HOSTED=1
 else
-SRC += swdptap.c jtagtap.c
 CFLAGS += -DPC_HOSTED=0
-VPATH += platforms/common
-CFLAGS += -Iplatforms/common
+include platforms/common/Makefile.inc
 endif
 
 ifeq ($(ENABLE_RTT), 1)
@@ -150,6 +147,9 @@ all_platforms:
 	$(MAKE) clean ;\
 	for i in platforms/*/Makefile.inc ; do \
 		export DIRNAME=`dirname $$i` ;\
+		if [ "$$DIRNAME" = "platforms/common" ]; then \
+			continue; \
+		fi; \
 		export PROBE_HOST=`basename $$DIRNAME` ;\
 		export CFLAGS=-Werror ;\
 		echo "Building for hardware platform: $$PROBE_HOST" ;\
diff --git a/src/platforms/common/Makefile.inc b/src/platforms/common/Makefile.inc
new file mode 100644
index 0000000..774faa8
--- /dev/null
+++ b/src/platforms/common/Makefile.inc
@@ -0,0 +1,27 @@
+#
+# This file is part of the Black Magic Debug project.
+#
+# Copyright (C) 2022 1BitSquared <info@1bitsquared.com>
+# Written by Rachel Mant <git@dragonmux.network>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+VPATH += platforms/common
+CFLAGS += -Iplatforms/common
+
+SRC +=        \
+	jtagtap.c \
+	swdptap.c \
+	usb.c     \
diff --git a/src/platforms/common/cdcacm.c b/src/platforms/common/cdcacm.c
index fe90c49..a987cbb 100644
--- a/src/platforms/common/cdcacm.c
+++ b/src/platforms/common/cdcacm.c
@@ -589,8 +589,3 @@ void cdcacm_init(void)
 	nvic_set_priority(USB_IRQ, IRQ_PRI_USB);
 	nvic_enable_irq(USB_IRQ);
 }
-
-void USB_ISR(void)
-{
-	usbd_poll(usbdev);
-}
diff --git a/src/platforms/common/cdcacm.h b/src/platforms/common/cdcacm.h
index 7cdfe23..db90011 100644
--- a/src/platforms/common/cdcacm.h
+++ b/src/platforms/common/cdcacm.h
@@ -28,7 +28,7 @@
 #ifndef __CDCACM_H
 #define __CDCACM_H
 
-#include <libopencm3/usb/usbd.h>
+#include "usb.h"
 
 #define CDCACM_PACKET_SIZE 	64
 
@@ -36,8 +36,6 @@
 #define CDCACM_UART_ENDPOINT	3
 #define TRACE_ENDPOINT			5
 
-extern usbd_device *usbdev;
-
 void cdcacm_init(void);
 /* Returns current usb configuration, or 0 if not configured. */
 int cdcacm_get_config(void);
diff --git a/src/platforms/common/usb.c b/src/platforms/common/usb.c
new file mode 100644
index 0000000..441984e
--- /dev/null
+++ b/src/platforms/common/usb.c
@@ -0,0 +1,27 @@
+/*
+ * This file is part of the Black Magic Debug project.
+ *
+ * Copyright (C) 2022 1BitSquared <info@1bitsquared.com>
+ * Written by Rachel Mant <git@dragonmux.network>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "general.h"
+#include "usb.h"
+
+void USB_ISR(void)
+{
+	usbd_poll(usbdev);
+}
diff --git a/src/platforms/common/usb.h b/src/platforms/common/usb.h
new file mode 100644
index 0000000..43b1fea
--- /dev/null
+++ b/src/platforms/common/usb.h
@@ -0,0 +1,28 @@
+/*
+ * This file is part of the Black Magic Debug project.
+ *
+ * Copyright (C) 2022 1BitSquared <info@1bitsquared.com>
+ * Written by Rachel Mant <git@dragonmux.network>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef USB_H
+#define USB_H
+
+#include <libopencm3/usb/usbd.h>
+
+extern usbd_device *usbdev;
+
+#endif /*USB_H*/