8 files changed, 48 insertions, 48 deletions
diff --git a/libmaple/usb/README b/libmaple/usb/README
index 2c55364..d0fca8d 100644
--- a/libmaple/usb/README
+++ b/libmaple/usb/README
@@ -1,35 +1,24 @@
-The USB submodule of libmaple is responsible for:
-
-    Initializing the USB peripheral, scaling the peripheral clocks
-    appropriately, enabling the interrupt channels to USB, defining
-    the USB IRQ, resetting the USB DISC pin (used to tell the host
-    were alive). Additionally, the USB submodule defines the virtual
-    COM port interface that is exposed to user sketches via SerialUSB.
-
-To use it:
-
-   SerialUSB.print/ln, available(), read(), write() implement the same
-   interface as Serial1/2/3.
+The USB submodule of libmaple is a separate piece of the codebase for
+reasons that are largely historical.
 
 Current Status:
 
-    Currently, the USB submodule relies on the low level core library
-    provided by ST to implement the USB transfer protocol for control
-    endpoint transfers.  The high level virtual com port application
-    is unfortunately hard to untangle from this low level dependence,
-    and when a new USB core library is written (to nix ST dependence)
-    changes will likely have to be made to virtual com application
-    code. Ideally, the new core library should mimic the form of MyUSB
-    (LUFA), since this library (USB for AVR) is growing in popularity
-    and in example applications.
+    There's only support for the USB device peripheral found on
+    STM32F103s.
 
-    The virtual com port serves two important purposes.
+    We rely on the low level core library provided by ST to implement
+    the USB transfer protocol for control endpoint transfers.
 
-      1) It allows serial data transfers between user sketches an a
-         host computer.
+    The virtual com port (which is exposed via
+    <libmaple/usb_cdcacm.h>) serves two important purposes.
 
-      2) It allows the host machine to issue a system reset by
-         asserting the DTR signal.
+    1) It allows serial data transfers between user sketches an a
+       host computer.
+
+    2) It allows the host PC to issue a system reset into the DFU
+       bootloader with the DTR + RTS + "1EAF" sequence (see
+       leaflabs.com/docs/bootloader.html for more information on
+       this).
 
     After reset, Maple will run the DFU bootloader for a few seconds,
     during which the user can begin a DFU upload operation (uploads
@@ -38,11 +27,11 @@ Current Status:
     the chip in order to enable the bootloader.
 
     If you would like to develop your own USB application for whatever
-    reason (uses faster isochronous enpoints for streaming audio, or
-    implements the USB HID or Mass Storage specs for examples) then
+    reason (e.g. to use faster isochronous enpoints for streaming
+    audio, or implement the USB HID or Mass Storage specs), then
     ensure that you leave some hook for resetting Maple remotely in
-    order to spin up the DFU bootloader.  Please make sure to give
-    yourself a unique vendor/product ID pair in your application, as
+    order to spin up the DFU bootloader.  Please make sure to get
+    yourself a unique vendor/product ID pair for your application, as
     some operating systems will assign a host-side driver based on
     these tags.
 
@@ -52,21 +41,23 @@ Current Status:
     be a burden from the host driver side, as Windows and *nix handle
     compound USB devices quite differently.
 
-    Be mindful that enabling the USB peripheral isnt "free." The
+    Be mindful that enabling the USB peripheral isn't "free." The
     device must respond to periodic bus activity (every few
     milliseconds) by servicing an ISR. Therefore, the USB application
-    should be disabled inside of timing critical applications. In
-    order to disconnect the device from the host, the USB_DISC pin can
-    be asserted (on Maple this is GPIO C12). Alternatively, the NVIC
+    should be disabled inside of timing critical applications.
+
+    In order to disconnect the device from the host, a USB_DISC pin is
+    asserted (e.g. on Maple, this is PC12). Alternatively, the NVIC
     can be directly configured to disable the USB LP/HP IRQ's.
 
     The files inside of usb_lib were provided by ST and are subject to
     their own license, all other files were written by the LeafLabs
     team and fall under the MIT license.
 
-Todo:
+TODO:
 
-    - write custom low level USB stack to strip out any remaining
-      dependence on ST code
-    - add a high level USB application library that would allow users
-      to make their own HID/Mass Storage/Audio/Video devices.
+    - Generic USB driver core with series-provided backends, like
+      libopencm3 has.
+    - Strip out ST code.
+    - Integration with a high level USB library (like LUFA/MyUSB) to
+      allow users to write custom USB applications.
diff --git a/libmaple/usb/rules.mk b/libmaple/usb/rules.mk
index 816fad6..e8ccc15 100644
--- a/libmaple/usb/rules.mk
+++ b/libmaple/usb/rules.mk
@@ -3,20 +3,29 @@ sp              := $(sp).x
 dirstack_$(sp)  := $(d)
 d               := $(dir)
 BUILDDIRS       += $(BUILD_PATH)/$(d)
-BUILDDIRS       += $(BUILD_PATH)/$(d)/usb_lib
 
 # Local flags
-CFLAGS_$(d) = -I$(d) -I$(d)/usb_lib $(LIBMAPLE_INCLUDES) $(LIBMAPLE_PRIVATE_INCLUDES) -Wall
+CFLAGS_$(d) = -I$(d) -I$(d)/$(MCU_SERIES) -I$(d)/usb_lib $(LIBMAPLE_INCLUDES) $(LIBMAPLE_PRIVATE_INCLUDES) -Wall
+
+# Add usblib and series subdirectory to BUILDDIRS.
+BUILDDIRS += $(BUILD_PATH)/$(d)/$(MCU_SERIES)
+BUILDDIRS += $(BUILD_PATH)/$(d)/usb_lib
 
 # Local rules and targets
 sSRCS_$(d) :=
-cSRCS_$(d) := usb.c                \
-              usb_reg_map.c        \
-              usb_cdcacm.c         \
-              usb_lib/usb_core.c   \
-              usb_lib/usb_init.c   \
-              usb_lib/usb_mem.c    \
-              usb_lib/usb_regs.c
+cSRCS_$(d) :=
+# We currently only have F1 performance line support. Sigh.
+ifeq ($(MCU_SERIES), stm32f1)
+ifeq ($(MCU_F1_LINE), performance)
+cSRCS_$(d) += $(MCU_SERIES)/usb.c
+cSRCS_$(d) += $(MCU_SERIES)/usb_reg_map.c
+cSRCS_$(d) += $(MCU_SERIES)/usb_cdcacm.c
+cSRCS_$(d) += usb_lib/usb_core.c
+cSRCS_$(d) += usb_lib/usb_init.c
+cSRCS_$(d) += usb_lib/usb_mem.c
+cSRCS_$(d) += usb_lib/usb_regs.c
+endif
+endif
 
 sFILES_$(d) := $(sSRCS_$(d):%=$(d)/%)
 cFILES_$(d) := $(cSRCS_$(d):%=$(d)/%)
diff --git a/libmaple/usb/usb.c b/libmaple/usb/stm32f1/usb.c
index 0130bab..0130bab 100644
--- a/libmaple/usb/usb.c
+++ b/libmaple/usb/stm32f1/usb.c
diff --git a/libmaple/usb/usb_cdcacm.c b/libmaple/usb/stm32f1/usb_cdcacm.c
index 6ef4806..6ef4806 100644
--- a/libmaple/usb/usb_cdcacm.c
+++ b/libmaple/usb/stm32f1/usb_cdcacm.c
diff --git a/libmaple/usb/usb_descriptors.h b/libmaple/usb/stm32f1/usb_descriptors.h
index 9bcb2b6..9bcb2b6 100644
--- a/libmaple/usb/usb_descriptors.h
+++ b/libmaple/usb/stm32f1/usb_descriptors.h
diff --git a/libmaple/usb/usb_lib_globals.h b/libmaple/usb/stm32f1/usb_lib_globals.h
index 1cd2754..1cd2754 100644
--- a/libmaple/usb/usb_lib_globals.h
+++ b/libmaple/usb/stm32f1/usb_lib_globals.h
diff --git a/libmaple/usb/usb_reg_map.c b/libmaple/usb/stm32f1/usb_reg_map.c
index 75562e1..75562e1 100644
--- a/libmaple/usb/usb_reg_map.c
+++ b/libmaple/usb/stm32f1/usb_reg_map.c
diff --git a/libmaple/usb/usb_reg_map.h b/libmaple/usb/stm32f1/usb_reg_map.h
index ce80842..ce80842 100644
--- a/libmaple/usb/usb_reg_map.h
+++ b/libmaple/usb/stm32f1/usb_reg_map.h