Tweak static analysis check BuildTest makefile argument order to make the call differ...
[pub/USBasp.git] / LUFA / DoxygenPages / MigrationInformation.txt
1 /** \file
2 *
3 * This file contains special DoxyGen information for the generation of the main page and other special
4 * documentation pages. It is not a project source file.
5 */
6
7 /** \page Page_Migration Migrating from Older Versions
8 *
9 * Below is migration information for updating existing projects based on previous versions of the LUFA library
10 * to the next version released. It does not indicate all new additions to the library in each version change, only
11 * areas relevant to making older projects compatible with the API changes of each new release.
12 *
13 * \section Sec_MigrationXXXXXX Migrating from 120219 to XXXXXX
14 * <b>Device Mode</b>
15 * - The device mode Audio Class driver now requires an additional configuration parameter, the Audio Control interface index. Existing applications should
16 * be adjusted to specify the additional configuration parameter.
17 *
18 * <b>Host Mode</b>
19 * - The Android Accessory Host class driver property strings are now a array of \c char* rather than a struct of named pointers. Existing applications
20 * should use C99 Designated Initializers with the property string indexes located in \ref AOA_Strings_t instead.
21 *
22 * \section Sec_Migration120219 Migrating from 111009 to 120219
23 * <b>USB Core</b>
24 * - The HID_KEYBOARD_MODIFER_* macros in the HID class driver have been corrected to HID_KEYBOARD_MODIFIER_* (note the spelling of "modifier").
25 * Existing applications should switch over to the correctly spelled macro names.
26 * - The names of the USB Device and USB Host class driver files have changed; a new "ClassDevice" and "ClassHost" postfix has been added to the
27 * respective class driver files. Projects referencing the class driver source files by filename rather than the LUFA_SRC_USBCLASS makefile
28 * variable should append these postfixes to the source file names. Projects including the USB class driver dispatch headers directly should either
29 * switch to including the main USB driver header instead, or use the updated header filenames.
30 * - The USB_CONFIG_ATTR_BUSPOWERED constant has been renamed to USB_CONFIG_ATTR_RESERVED, as this was misnamed. All devices must set this bit in
31 * the Configuration descriptor's attributes field. As all devices are assumed to be bus-powered unless stated otherwise with the
32 * USB_CONFIG_ATTR_SELFPOWERED flag a replacement constant for bus powered devices is not provided.
33 *
34 * <b>Device Mode</b>
35 * - The device mode Audio class driver now requires a new user application callback, \ref CALLBACK_Audio_Device_GetSetInterfaceProperty().
36 * Existing applications must implement this new callback, however if no audio entities are defined in the audio device's descriptors,
37 * this function may be hard-coded to always return false for previous behaviour to be retained.
38 *
39 * \section Sec_Migration111009 Migrating from 110528 to 111009
40 * <b>Non-USB Library Components</b>
41 * - The \c JTAG_DEBUG_ASSERT() macro has been renamed \ref JTAG_ASSERT() to be consistent with \ref STDOUT_ASSERT().
42 *
43 * <b>USB Core</b>
44 * - By default, unordered Endpoint and Pipe configuration is now allowed once again, via the previous workaround of
45 * reconfiguring all Endpoints/Pipes in order each time a new Endpoint/Pipe is created. To minimize the compiled program
46 * size, the new \c ORDERED_EP_CONFIG compile time option may be defined in the project makefile to restrict the ordering
47 * in exchange for a smaller compiled binary size.
48 * - The previous \c F_CLOCK symbol, required in the project makefile, has been renamed to \c F_USB. This is due to the previous name
49 * being far too generic for use in future architecture ports, where multiple clock domains are used.
50 *
51 * <b>Device Mode</b>
52 * - The Endpoint stream functions now all require a \c BytesProcessed parameter instead of the previous callback parameter.
53 * This should be set to \c NULL to retain previous behaviour of the functions, or point to a location where the number of bytes
54 * processed in the current transaction can be stored. If the \c BytesProcessed parameter is non \c NULL, each time the endpoint
55 * bank becomes full and the packet is sent, the routine will exit with the new \ref ENDPOINT_RWSTREAM_IncompleteTransfer
56 * error code to allow the user application to determine when to send the next chunk of data.
57 * - The \ref CDC_Device_SendString() function now expects a null terminated string instead of an explicit length. Existing code
58 * should use the new \ref CDC_Device_SendData() function, or remove the length parameter from the function call.
59 * - The \c Endpoint_ResetFIFO() function has been renamed to \ref Endpoint_ResetEndpoint(), to make the API function names more
60 * consistent. Existing applications using the old function name should simply replace it with a call to the new function name.
61 * - The \c Endpoint_*_Byte() functions have been renamed Endpoint_*_8() to ensure they are correct across all architectures. Existing
62 * code using these functions should replace the previous function names with the new function names.
63 * - The \c Endpoint_*_Word() functions have been renamed Endpoint_*_16() to ensure they are correct across all architectures. Existing
64 * code using these functions should replace the previous function names with the new function names.
65 * - The \c Endpoint_*_DWord() functions have been renamed Endpoint_*_32() to ensure they are correct across all architectures. Existing
66 * code using these functions should replace the previous function names with the new function names.
67 * - The Device mode RNDIS class driver no longer stores the incoming and outgoing packets in the class driver instance; the user is
68 * now expected to manually define a storage location for the packet data. Packets must now be sent and received manually via a call
69 * to \ref RNDIS_Device_ReadPacket() and/or \ref RNDIS_Device_SendPacket().
70 * - The definition of the Audio class \ref USB_Audio_Descriptor_Format_t has been altered, to remove the fixed singular
71 * audio sample rate in the descriptor definition, and to rename the \c SampleFrequencyType to the more appropriate
72 * \c TotalDiscreteSampleRates. Existing applications will need to add an array of \ref USB_Audio_SampleFreq_t elements
73 * immediately following any \ref USB_Audio_Descriptor_Format_t descriptors, and insert the appropriate sampling rates
74 * supported by the device, as well as rename the descriptor elements to match the updated element names.
75 * - The device mode Audio class driver now requires a new user application callback, \ref CALLBACK_Audio_Device_GetSetEndpointProperty().
76 * Existing applications must implement this new callback, however if multiple sample rates or pitch control is not used,
77 * this function may be hard-coded to always return false for previous behaviour to be retained.
78 * - The \c USB_ConfigurationNumber, \c USB_RemoteWakeupEnabled and \c USB_CurrentlySelfPowered globals have been renamed to
79 * \ref USB_Device_ConfigurationNumber, \ref USB_Device_RemoteWakeupEnabled and \ref USB_Device_CurrentlySelfPowered to clearly indicate
80 * the USB mode they relate to. Existing applications using these variables should rename all references to the previous names.
81 * - The \c ENDPOINT_DESCRIPTOR_DIR_IN and \c ENDPOINT_DESCRIPTOR_DIR_OUT macros have now been replaced by \ref ENDPOINT_DIR_IN and
82 * \ref ENDPOINT_DIR_OUT to improve code clarity.
83 * - The \ref HID_DESCRIPTOR_JOYSTICK() macro now takes an additional (first) parameter indicating the number of axis in the joystick.
84 *
85 * <b>Host Mode</b>
86 * - The Pipe stream functions now all require a \c BytesProcessed parameter instead of the previous callback parameter.
87 * This should be set to \c NULL to retain previous behaviour of the functions, or point to a location where the number of bytes
88 * processed in the current transaction can be stored. If the BytesProcessed parameter is non \c NULL, each time the pipe
89 * bank becomes full and the packet is sent, the routine will exit with the new \ref PIPE_RWSTREAM_IncompleteTransfer
90 * error code to allow the user application to determine when to send the next chunk of data.
91 * - The \ref PRNT_Host_SendString() and \ref CDC_Host_SendString() functions now expect a null terminated string instead of an explicit
92 * length. Existing code should use the new \ref PRNT_Host_SendData() and \ref CDC_Host_SendData() functions, or remove the
93 * length parameter from the function call.
94 * - The \c Pipe_ClearErrorFlags() function has been removed, as the pipe error flags are now automatically cleared when the
95 * \ref Pipe_ClearError() function is called.
96 * - The \c Pipe_*_Byte() functions have been renamed Pipe_*_8() to ensure they are correct across all architectures. Existing code using
97 * these functions should replace the previous function names with the new function names.
98 * - The \c Pipe_*_Word() functions have been renamed Pipe_*_16() to ensure they are correct across all architectures. Existing code using
99 * these functions should replace the previous function names with the new function names.
100 * - The \c Pipe_*_DWord() functions have been renamed Pipe_*_32() to ensure they are correct across all architectures. Existing code using
101 * these functions should replace the previous function names with the new function names.
102 * - The \c USB_Host_ClearPipeStall() function has been renamed to USB_Host_ClearEndpointStall(), as it operates on a full endpoing address
103 * within the attached device and not a pipe within the host. Existing code using the old function name should update the function calls and
104 * check for correct usage.
105 *
106 * \section Sec_Migration101122 Migrating from 100807 to 101122
107 * <b>USB Core</b>
108 * - A new USB driver source file, \c Drivers/USB/HighLevel/EndpointStream.c now exists. This source file should be added
109 * to all project makefiles using the USB driver of LUFA, or the makefile should be updated to use the new module source
110 * variables.
111 * - A new USB driver source file, \c Drivers/USB/HighLevel/PipeStream.c now exists. This source file should be added to all
112 * project makefiles using the USB driver of LUFA, or the makefile should be updated to use the new module source variables.
113 * - The \c EVENT_USB_InitFailure() event has been removed, as the \ref USB_Init() function will no longer fail; if not USB mode is
114 * specified, the controller will default to UID selection mode.
115 * - The USB mode specifier constants have been moved into a new enum and renamed. Existing projects should use the equivalent
116 * value in the new \ref USB_Modes_t enum.
117 * - All class driver headers are now included as part of the standard \c LUFA/Drivers/USB/USB.h master dispatch header, and should
118 * no longer be included separately. Class driver module source files must still be added as a separate module in the project's
119 * makefile if used.
120 *
121 * <b>Device Mode</b>
122 * - Endpoints MUST be allocated in ascending order to ensure that bank corruption does not occur. Ensure that your user application
123 * allocated endpoints in ascending order - or if your application uses the USB device mode class drivers, ensure that each instance's
124 * endpoint indexes are not overlapped with other interface's endpoints.
125 * - The signature for the \ref CALLBACK_USB_GetDescriptor() callback has changed, the \c void** \c const \c DescriptorAddress parameter is
126 * now \c const \c void** \c const \c DescriptorAddress. Existing applications should update their callback signatures to match this, and
127 * eliminate any casting of descriptor pointers to a non \c const pointer.
128 * - The names of the class specific descriptor type defines in the USB Class drivers have changed - refer to the driver documentation
129 * for each class driver for the new class specific descriptor type names.
130 * - The \c ENDPOINT_DOUBLEBANK_SUPPORTED() macro is has been renamed \ref ENDPOINT_BANKS_SUPPORTED() and now returns the total number of
131 * banks supported by the given endpoint. Existing code should switch to the new naming scheme, and test that the return value of the
132 * macro is equal to or greater than 2 to regain the previous functionality.
133 * - The \c EVENT_USB_Device_UnhandledControlRequest() event is now named \ref EVENT_USB_Device_ControlRequest() and fires before (not after)
134 * the internal library event handlers. Existing code should rename the event handlers in the user application to match the new event
135 * name, and should ensure that the new execution order does not affect the application's operation.
136 *
137 * <b>Host Mode</b>
138 * - Pipes MUST be allocated in ascending order to ensure that bank corruption does not occur. Ensure that your user application
139 * allocated pipes in ascending order - or if your application uses the USB host mode class drivers, ensure that each instance's
140 * pipe indexes are not overlapped with other interface's pipes.
141 * - The \c PRNT_Host_SendData() function has been renamed to \ref PRNT_Host_SendString(). Existing applications should simply
142 * replace all references to the obsolete function name with the new function name.
143 * - The names of the class specific descriptor type defines in the USB Class drivers have changed - refer to the driver documentation
144 * for each class driver for the new class specific descriptor type names.
145 * - The Still Image Host class' function prefix has been changed from \c SImage_ to \c SI_, to remain consistent with the rest of the
146 * driver's enums, type defines and constants.
147 *
148 * \section Sec_Migration100807 Migrating from 100513 to 100807
149 *
150 * <b>Non-USB Library Components</b>
151 * - The Dataflash board driver stub file has changed, as dataflash functions previously located in the internal
152 * Dataflash driver of the library have now been moved to the individual board files. Existing drivers can
153 * copy-paste the new functions from the board Dataflash stub driver.
154 *
155 * <b>USB Core</b>
156 * - A new USB driver source file, \c Drivers/USB/LowLevel/Device.c now exists. This source file should be added to all project
157 * makefiles using the USB driver of LUFA, or the makefile should be updated to use the new module source variables.
158 * - The \c Drivers/USB/LowLevel/DevChapter9.c source file has moved to \c Drivers/USB/HighLevel/DeviceStandardReq.c - this should
159 * be updated in all project makefiles, or the makefile should be updated to use the new module source variables.
160 * - The \c Drivers/USB/LowLevel/HostChapter9.h source file has moved to \c Drivers/USB/HighLevel/HostStandardReq.c - this should
161 * be updated in all project makefiles, or the makefile should be updated to use the new module source variables.
162 * - The \c Drivers/USB/LowLevel/LowLevel.c source file has moved to \c Drivers/LowLevel/USBController.c - this should be updated
163 * in all project makefiles, or the makefile should be updated to use the new module source variables.
164 *
165 * <b>Device Mode</b>
166 * - The \c USB_Device_IsRemoteWakeupSent() macro has been removed, as the remote wakeup request is now fully handled by the
167 * enhanced \ref USB_Device_SendRemoteWakeup() function. Existing code may now discard any checks to \c USB_Device_IsRemoteWakeupSent().
168 * - The \c USB_Device_IsUSBSuspended() macro has been removed, as it is obsolete. Existing code should compare \ref USB_DeviceState
169 * to see if it the device is in the \ref DEVICE_STATE_Suspended state instead.
170 * - The \ref CDC_Device_ReceiveByte() function has changed, and now returns a signed 16-bit integer, with -1 indicating no data was
171 * received. This allows for more efficient coding, as a call to \ref CDC_Device_BytesReceived() is no longer needed if the exact
172 * number of queued bytes received is not needed.
173 *
174 * <b>Host Mode</b>
175 * - The \ref CDC_Host_ReceiveByte() function has changed, and now returns a signed 16-bit integer, with -1 indicating no data was
176 * received. This allows for more efficient coding, as a call to \ref CDC_Host_BytesReceived() is no longer needed if the exact
177 * number of queued bytes received is not needed.
178 * - The \ref CDC_Host_USBTask() now calls \ref CDC_Host_Flush() automatically, flushing any queued data to the attached device. Manual
179 * flushing of the interface is no longer needed if the flushes should be in sync with calls to \ref CDC_Host_USBTask().
180 *
181 * \section Sec_Migration100513 Migrating from 100219 to 100513
182 *
183 * <b>Non-USB Library Components</b>
184 * - The \ref TWI_StartTransmission() function now takes in a timeout period, expressed in milliseconds, within which the addressed
185 * device must respond or the function will abort.
186 *
187 * <b>Device Mode</b>
188 * - The \ref USB_Init() function no longer calls \c sei() to enable global interrupts, as the user application may need
189 * to perform other initialization before it is ready to handle global interrupts. The user application is now responsible
190 * for enabling global interrupts before or shortly after calling \ref USB_Init() to ensure that the enumeration process
191 * functions correctly.
192 * - The \c USBInterrupt.c USB driver source file has been relocated from \c LUFA/Drivers/USB/HighLevel/ to \c LUFA/Drivers/USB/LowLevel.
193 * Projects must update their makefile SRC values accordingly.
194 * - The HID Device Class driver's function signature for the \ref CALLBACK_HID_Device_ProcessHIDReport() function has been changed, to
195 * allow for a new \c ReportType parameter. This new parameter must be added in all user applications using the Device mode HID Class
196 * Driver, but may be ignored unless Host-to-Device FEATURE HID reports are used.
197 *
198 * <b>Host Mode</b>
199 * - The \ref USB_Init() function no longer calls \c sei() to enable global interrupts, as the user application may need
200 * to perform other initialization before it is ready to handle global interrupts. The user application is now responsible
201 * for enabling global interrupts before or shortly after calling \ref USB_Init() to ensure that the enumeration process
202 * functions correctly.
203 * - The \c USBInterrupt.c USB driver source file has been relocated from \c LUFA/Drivers/USB/HighLevel/ to \c LUFA/Drivers/USB/LowLevel.
204 * Projects must update their makefile \c SRC values accordingly.
205 * - The HID Host Class driver's function signature for the \ref HID_Host_SendReportByID() function has been changed, to allow for a new
206 * ReportType parameter. Existing calls to this function should substitute \c REPORT_ITEM_TYPE_Out as this parameter's value.
207 *
208 * \section Sec_Migration100219 Migrating from 091223 to 100219
209 *
210 * <b>Non-USB Library Components</b>
211 * - Due to some ADC channels not being identical to their ADC MUX selection masks for single-ended conversions on some AVR models,
212 * the ADC driver now has explicit masks for each of the standard ADC channels (see \ref Group_ADC). These masks should be used
213 * when calling the ADC functions to ensure proper operation across all AVR models. Note that the \ref ADC_SetupChannel() function
214 * is an exception, and should always be called with a channel number rather than a channel mask.
215 *
216 * <b>Host Mode</b>
217 * - The MIDI Host Class driver send and receive routines now operate on packed events, where multiple MIDI events may be
218 * packed into a single USB packet. This means that the sending of MIDI events will now be delayed until the MIDI send
219 * pipe bank is full. To override this new behaviour and revert to the previous behaviour, the user application may manually
220 * flush the queued event(s) to the device by calling \ref MIDI_Host_Flush().
221 * - The \ref Pipe_IsEndpointBound() function now takes the endpoint's direction into account, by checking if the MSB of the endpoint's address
222 * is set to denote IN endpoints. If the previous functionality where the direction is to be discounted is required, mask the endpoint
223 * address against the \ref PIPE_EPNUM_MASK token before calling \ref Pipe_IsEndpointBound().
224 *
225 * <b>Device Mode</b>
226 * - The MIDI Device Class driver send and receive routines now operate on packed events, where multiple MIDI events may be
227 * packed into a single USB packet. This means that the sending of MIDI events will now be delayed until the MIDI send
228 * endpoint bank is full. To override this new behaviour and revert to the previous behaviour, the user application may manually
229 * flush the queued event(s) to the host by calling \ref MIDI_Device_Flush().
230 *
231 * \section Sec_Migration091223 Migrating from 091122 to 091223
232 *
233 * <b>Host Mode</b>
234 * - The Still Image Host Class driver \ref SI_Host_USBTask() and \ref SI_Host_ConfigurePipes() functions were misnamed, and are
235 * now named \c SImage_Host_USBTask() and \c SImage_Host_ConfigurePipes() respectively.
236 * - The \c HOST_SENDCONTROL_DeviceDisconnect enum value has been renamed to \ref HOST_SENDCONTROL_DeviceDisconnected to be in
237 * line with the rest of the library error codes.
238 * - The HID Parser item usages no longer contain separate minimum and maximum values, as this was a violation of the HID
239 * specification. Instead, the values are distributed evenly across each item as its usage value, to ensure that all items
240 * can be distinguished from one-another.
241 *
242 * <b>Device Mode</b>
243 * - The \ref CALLBACK_HID_Device_CreateHIDReport() HID Device Class driver callback now has a new \c ReportType parameter to
244 * indicate the report type to generate. Existing applications may simply add and ignore this additional parameter.
245 *
246 * \section Sec_Migration091122 Migrating from 090924 to 091122
247 *
248 * <b>Host Mode</b>
249 * - The \c HID_PARSE_UsageStackOverflow HID parser error constant is now named \ref HID_PARSE_UsageListOverflow
250 * - The \ref CALLBACK_HIDParser_FilterHIDReportItem() HID Parser callback now passes a complete \ref HID_ReportItem_t to the
251 * user application, instead of just its attributes.
252 * - The \c USB_GetDeviceConfigDescriptor() function was incorrectly named and is now called \ref USB_Host_GetDeviceConfigDescriptor().
253 *
254 * \section Sec_Migration090924 Migrating from 090810 to 090924
255 *
256 * <b>Non-USB Library Components</b>
257 * - The \c ADC_Off() function has been renamed to \c ADC_ShutDown() to be consistent with the rest of the library.
258 * - The \ref SPI_Init() routine's parameters have changed, so that the clock polarity and data sampling modes can be set. See
259 * the \ref SPI_Init() function documentation for more details
260 * - The \ref Dataflash_Init() routine no longer initializes the SPI bus - the SPI bus should be initialized manually via a
261 * call to \ref SPI_Init() before using the Dataflash driver
262 *
263 * <b>Host Mode</b>
264 * - The \c USB_GetDeviceConfigDescriptor() function's parameters and behaviour has changed; the user is required to
265 * preallocate the largest allowable buffer, and pass the size of the buffer to the function. This allows for a single
266 * call to the function to retrieve, size check and validate the Configuration Descriptor rather than having the user
267 * application perform these intermediary steps.
268 * - The HID report parser now requires a mandatory callback in the user code, to filter only the items the application
269 * is interested in into the processed HID report item structure to save RAM. See \ref CALLBACK_HIDParser_FilterHIDReportItem().
270 * - The HID report parser now always parses FEATURE and always ignores constant-data items - the \c HID_ENABLE_FEATURE_PROCESSING
271 * and \c HID_INCLUDE_CONSTANT_DATA_ITEMS compile time tokens now have no effect.
272 * - The \c USE_NONSTANDARD_DESCRIPTOR_NAMES compile time token has been removed - there are now separate \c USB_Descriptor_*
273 * and \c USB_StdDescriptor_* structures for both the LUFA and standardized element naming conventions so that both may be used in
274 * the one project. For existing projects using the standardized names, change all code to use the \c USB_StdDescriptor_* variants.
275 *
276 * <b>Device Mode</b>
277 * - The \c USE_NONSTANDARD_DESCRIPTOR_NAMES compile time token has been removed - there are now separate \c USB_Descriptor_*
278 * and \c USB_StdDescriptor_* structures for both the LUFA and standardized element naming conventions so that both may be used in
279 * the one project. For existing projects using the standardized names, change all code to use the \c USB_StdDescriptor_* variants.
280 *
281 * \section Sec_Migration090810 Migrating from 090605 to 090810
282 *
283 * <b>All</b>
284 * - The "Simple Scheduler" has been <i>deprecated</i>, as it was little more than an abstracted loop and caused much confusion.
285 * User applications using the scheduler should switch to regular loops instead. The scheduler code will be removed in a future
286 * release.
287 * - The "Dynamic Memory Block Allocator" has been removed, as it was unused in (and unrelated to) the LUFA library and never
288 * used in user applications.
289 *
290 * <b>Non-USB Library Components</b>
291 * - The \c ATTR_NOINLINE function attribute macro has been renamed to \ref ATTR_NO_INLINE to be in line with the rest of the function attribute
292 * macro names.
293 *
294 * <b>Library Demos</b>
295 * - Most demos now have a corresponding Class Driver implementation, which uses the new internal library class drivers for the standard
296 * USB classes. This allows for more rapid device and host development, and so should be used in preference to the low level APIs where
297 * possible so that fixes to the class drivers propagate to all applications which use them automatically with each new LUFA release.
298 *
299 * <b>Host Mode</b>
300 * - The \c HIDParser.c module has moved from \c LUFA/Drivers/USB/Class/ to \c LUFA/Drivers/USB/Class/Host/.
301 * - The \c USB_GetDeviceConfigDescriptor() function now requires the desired configuration index within the device as its first
302 * parameter, to add support for multi-configuration devices. Existing code should use a configuration index of 1 to indicate the
303 * first configuration descriptor within the device.
304 * - The non-standard "Ready" host state has been removed. Existing \ref HOST_STATE_Configured code should be moved to the end of
305 * the existing \ref HOST_STATE_Addressed state, and the existing HOST_STATE_Ready state code should be moved to the \ref HOST_STATE_Configured
306 * state.
307 * - The \c USB_IsConnected global has been removed, as it is too vague for general use. Test \ref USB_HostState explicitly to ensure the host is
308 * in the desired state instead.
309 * - The USB event names have been changed and their firing conditions changed to properly separate out Host mode events from Device mode
310 * events. See the \ref Group_Events page for details on the new event names and firing conditions.
311 *
312 * <b>Device Mode</b>
313 * - The \ref CALLBACK_USB_GetDescriptor() function now takes an extra parameter to specify the descriptor's memory space so that
314 * descriptors in mixed memory spaces can be used. The previous functionality can be returned by defining the \c USE_FLASH_DESCRIPTORS
315 * token in the project makefile to fix all descriptors into FLASH space and remove the extra function parameter.
316 * - The \c USB_IsSuspended global has been removed - test \ref USB_DeviceState against \ref DEVICE_STATE_Suspended instead.
317 * - The \c USB_IsConnected global has been removed, as it is too vague for general use. Test \ref USB_DeviceState explicitly to ensure the device
318 * is in the desired state instead.
319 * - The VBUS events have been removed, as they are already exposed to the user via the \c USB_Connect and \c USB_Disconnect events.
320 * - The USB event names have been changed and their firing conditions changed to properly separate out Host mode events from Device mode
321 * events. See the \ref Group_Events page for details on the new event names and firing conditions.
322 *
323 * \section Sec_Migration090605 Migrating from 090510 to 090605
324 *
325 * <b>Device Mode</b>
326 * - Support for non-control data endpoint interrupts has been dropped due to many issues in the implementation. All existing
327 * projects using interrupts on non-control endpoints should switch to polling. For control interrupts, the library can
328 * manage the control endpoint via interrupts automatically by compiling with the \c INTERRUPT_CONTROL_ENDPOINT token defined.
329 * - The \c DESCRIPTOR_ADDRESS() macro has been removed. User applications should use normal casts to obtain a descriptor's memory
330 * address.
331 * - The library events system has been rewritten, so that all macros have been removed to allow for clearer user code. See
332 * \ref Group_Events for new API details.
333 * - The \c STREAM_CALLBACK() macro has been removed. User applications should replace all instances of the macro with regular
334 * function signatures of a function accepting no arguments and returning a \c uint8_t value.
335 * - The \c Event_DeviceError() event no longer exists, as its sole caller (unlinked \c USB_GetDescriptor() function) now produces a
336 * compilation error rather than a runtime error. The \c StdDescriptors.c file no longer exists as a result, and should be removed
337 * from project makefiles.
338 * - The \c USB_GetDescriptor() function has been renamed to \ref CALLBACK_USB_GetDescriptor() to be in line with the new \c CALLBACK_
339 * function prefixes for functions which <i>must</i> be implemented in the user application.
340 *
341 * <b>Host Mode</b>
342 * - Support for non-control data pipe interrupts has been dropped due to many issues in the implementation. All existing
343 * projects using interrupts on non-control pipes should switch to polling.
344 * - The library events system has been rewritten, so that all macros have been removed to allow for clearer user code. See
345 * \ref Group_Events for new API details.
346 * - The \c STREAM_CALLBACK() macro has been removed. User applications should replace all instances of the macro with regular
347 * function signatures of a function accepting no arguments and returning a \c uint8_t value.
348 * - The \c DESCRIPTOR_COMPARATOR() macro has been removed. User applications should replace all instances of the macro with
349 * regular function signatures of a function accepting a void pointer to the descriptor to test, and returning a \c uint8_t value.
350 *
351 * \section Sec_Migration090510 Migrating from 090401 to 090510
352 *
353 * <b>All</b>
354 * - The \c ButtLoadTag.h header has been removed, as it was never used for its intended purpose. Projects should either remove all
355 * \c BUTTLOADTAG() elements, or download and extract \c ButtLoadTag.h header from the ButtLoad project.
356 * - The \c Drivers/AT90USBXXX/ directory has been renamed to \c Drivers/Peripheral/.
357 * - The \c Serial_Stream driver has been renamed to \c SerialStream to remain consistent with the rest of the library naming scheme.
358 * - The HWB driver has changed to the \c Buttons driver. See the board Buttons driver documentation for the new API.
359 *
360 * <b>Dual Role Mode</b>
361 * - The \c USB_PowerOnFail event has been renamed to \c USB_InitFailure.
362 * - The functions in \c OTG.h have been renamed to remain more consistent with the library API. See the functions in \c OTG.h for more
363 * details.
364 *
365 * <b>Device Mode</b>
366 * - The \c Endpoint_ClearCurrentBank() macro has been removed, and is now replaced with the \ref Endpoint_ClearIN(), \ref Endpoint_ClearOUT()
367 * macros. See \c Endpoint.h documentation for more details on the new endpoint management macros.
368 * - The \c Endpoint_ReadWriteAllowed() macro has been renamed to \ref Endpoint_IsReadWriteAllowed() to be more consistent with the rest of
369 * the API naming scheme.
370 * - The \c Endpoint_IsSetupINReady() and \c Endpoint_IsSetupOUTReceived() macros have been renamed to \ref Endpoint_IsINReady() and
371 * \ref Endpoint_IsOUTReceived() respectively.
372 * - The \c Endpoint_IsSetupReceived() macro has been renamed to \ref Endpoint_IsSETUPReceived().
373 * - The \c Endpoint_ClearSetupReceived() macro has been renamed to \ref Endpoint_ClearSETUP().
374 * - All endpoint read/write/discard aliases which did not have an explicitly endianness specifier (such as \c Endpoint_Read_Word()) have
375 * been removed for clarity. Existing projects should use the \c _LE suffix on such calls to use the explicit Little Endian versions.
376 * - The \c USB_UnhandledControlPacket event no longer has any parameters. User code should no longer attempt to read in the remainder of
377 * the Control Request header as all Control Request header data is now preloaded by the library and made available in the
378 * USB_ControlRequest structure.
379 * - The \c FEATURELESS_CONTROL_ONLY_DEVICE token has been renamed to \c CONTROL_ONLY_DEVICE.
380 * - The \c STATIC_ENDPOINT_CONFIGURATION is no longer applicable as the library will apply this optimization when appropriate automatically.
381 * - The values of the \ref Endpoint_Stream_RW_ErrorCodes_t and \ref Endpoint_ControlStream_RW_ErrorCodes_t enums have had the \c ERROR_ portion
382 * of their names removed.
383 *
384 * <b>Host Mode</b>
385 * - The \ref USB_Host_SendControlRequest() function no longer automatically selects the Control pipe (pipe 0) to allow it to be used on
386 * other control type pipes. Care should be taken to ensure that the Control pipe is always selected before the function is called
387 * in existing projects where the Control pipe is to be operated on.
388 * - The USB Host management task now saves and restores the currently selected pipe before and after the task runs. Projects no longer
389 * need to manage this manually when calling the USB management task.
390 * - The \c Pipe_ClearCurrentBank() macro has been removed, and is now replaced with the Pipe_ClearIN(), Pipe_ClearOUT() macros. See
391 * Pipe.h documentation for more details on the new pipe management macros.
392 * - The \c Pipe_ReadWriteAllowed() macro has been renamed to \ref Pipe_IsReadWriteAllowed() to be more consistent with the rest of the API
393 * naming scheme.
394 * - The \c Pipe_IsSetupINReceived() and \c Pipe_IsOutReady() macros have been renamed to \ref Pipe_IsINReceived() and \ref Pipe_IsOUTReady()
395 * respectively.
396 * - The new \ref Pipe_ClearSETUP() macro should be used to send SETUP transactions, rather than the previous \c Pipe_ClearSetupOUT() macro.
397 * - The \c Pipe_IsSetupSent() macro has been renamed to \ref Pipe_IsSETUPSent().
398 * - The \c Pipe_ClearSetupSent() macro is no longer applicable and should be removed.
399 * - All pipe read/write/discard aliases which did not have an explicitly endianness specifier (such as \c Pipe_Read_Word()) have
400 * been removed for clarity. Existing projects should use the \c _LE suffix on such calls to use the explicit Little Endian versions.
401 * - The \c Host_IsResetBusDone() macro has been renamed to \c Host_IsBusResetComplete().
402 * - The \c Pipe_Ignore_Word() and \c Pipe_Ignore_DWord() functions have been renamed to \c Pipe_Discard_Word() and \c Pipe_Discard_DWord()
403 * to remain consistent with the rest of the pipe API.
404 * - It is no longer needed to manually include the headers from \c LUFA/Drivers/USB/Class, as they are now included along with the rest
405 * of the USB headers when \c LUFA/Drivers/USB/USB.h is included.
406 * - Functions in the \c ConfigDescriptor.h header file no longer have \c Host_ as part of their names.
407 * - The \c ProcessHIDReport() has been renamed to \ref USB_ProcessHIDReport(), \c GetReportItemInfo() has been renamed to \ref USB_GetHIDReportItemInfo()
408 * and \c SetReportItemInfo() has been renamed to \ref USB_GetHIDReportItemInfo().
409 * - The values of the \ref DSearch_Return_ErrorCodes_t and \ref DSearch_Comp_Return_ErrorCodes_t enums have had their respective \c Descriptor_Search
410 * and \c Descriptor_Search_Comp prefixes changed to all caps.
411 * - The \c USB_HostRequest global has been renamed to \ref USB_ControlRequest, and is used in Device mode also. The \c USB_Host_Request_Header_t
412 * structure type has been renamed to \ref USB_Request_Header_t.
413 * - The values of the \ref Pipe_Stream_RW_ErrorCodes_t enum have had the \c ERROR_ portion of their names removed.
414 *
415 * \section Sec_Migration090401 Migrating from 090209 to 090401
416 *
417 * <b>All</b>
418 * - LUFA projects must now give the raw input clock frequency (before any prescaling) as a compile time constant \c F_USB,
419 * defined in the project makefile and passed to the compiler via the -D switch.
420 * - The makefile EEPROM programming targets for FLIP and dfu-programmer no longer program in the FLASH data in addition to the
421 * EEPROM data into the device. If both are to be programmed, both the EEPROM and FLASH programming targets must be called.
422 * - As the avr-libc macro has been corrected in recent avr-libc distributions, the \c SetSystemClockPrescaler() macro has been removed.
423 * Include \c <avr/power.h> and call \c clock_prescale_set(clock_div_1); instead on recent avr-libc distributions.
424 *
425 * <b>Library Demos</b>
426 * - The USBtoSerial demo now discards all data when not connected to a host, rather than buffering it for later transmission.
427 *
428 * <b>Non-USB Library Components</b>
429 * - The \c ATTR_ALWAYSINLINE function attribute macro has been renamed to \ref ATTR_ALWAYS_INLINE.
430 * - Custom board Dataflash drivers now require the implementation of \ref Dataflash_SelectChipFromPage() and \ref Dataflash_SendAddressBytes().
431 *
432 * <b>Device Mode</b>
433 * - The \c NO_CLEARSET_FEATURE_REQUEST compile time token has been renamed to \c FEATURELESS_CONTROL_ONLY_DEVICE, and its function expanded
434 * to also remove parts of the Get Status chapter 9 request to further reduce code usage. On all applications currently using the
435 * \c NO_CLEARSET_FEATURE_REQUEST compile time token, it can be replaced with the \c FEATURELESS_CONTROL_ONLY_DEVICE token with no further
436 * modifications required.
437 *
438 * \section Sec_Migration090209 Migrating from 081217 to 090209
439 *
440 * <b>Device Mode</b>
441 * - The \c ENDPOINT_MAX_ENDPOINTS constant has been renamed to the more appropriate name of \c ENDPOINT_TOTAL_ENDPOINTS.
442 * - The \c USB_STREAM_TIMEOUT_MS stream timeout default period has been extended to 100ms. This can be overridden in the user
443 * makefile if desired to restore the previous 50ms timeout.
444 *
445 * <b>Host Mode</b>
446 * - The \c PIPE_MAX_ENDPOINTS constant has been renamed to the more appropriate name of \c PIPE_TOTAL_ENDPOINTS.
447 * - The \c USB_STREAM_TIMEOUT_MS stream timeout default period has been extended to 100ms. This can be overridden in the user
448 * makefile if desired to restore the previous 50ms timeout.
449 * - The \c USB_DeviceEnumerationFailed event now contains a second \c SubErrorCode parameter, giving the error code of the function
450 * which failed.
451 * - The \c HID_PARSE_Sucessful enum member constant name has been corrected to \ref HID_PARSE_Successful.
452 *
453 * <b>Non-USB Library Components</b>
454 * - The previous \c SPI_SendByte() functionality is now located in \ref SPI_TransferByte(). \ref SPI_SendByte() now discards the return byte
455 * for speed, to compliment the new \ref SPI_ReceiveByte() function. If bidirectional SPI transfers are required, calls to \ref SPI_SendByte()
456 * should be changed to \ref SPI_TransferByte().
457 * - The serial driver now sets the Tx line as an output explicitly, and enables the pull-up of the Rx line.
458 * - The \ref Serial_Init() and \c SerialStream_Init() functions now take a second \c DoubleSpeed parameter, which indicates if the USART
459 * should be initialized in double speed mode - useful in some circumstances for attaining baud rates not usually possible at the given AVR
460 * clock speed.
461 *
462 * \section Sec_Migration171208 Migrating from V1.5.3 to 081217
463 *
464 * <b>All</b>
465 * - The MyUSB project name has been changed to LUFA (Lightweight Framework for USB AVRs). All references to MyUSB, including macro names,
466 * have been changed to LUFA.
467 *
468 * <b>Library Demos</b>
469 * - The ReconfigureUSART() routine in the USBtoSerial demo was not being called after new line encoding
470 * parameters were set by the host. Projects built on the USBtoSerial code should update to the latest version.
471 * - The HID Parser now supports multiple report (on a single endpoint) HID devices. The MouseHostWithParser and
472 * KeyboardHostWithPaser demos use the updated API functions to function correctly on such devices. Projects
473 * built on either "WithParser" demo should update to the latest code.
474 * - The RNDIS demo TCP stack has been modified so that connections can be properly closed. It is still not
475 * recommended that the MyUSB RNDIS demo TCP/IP stack be used for anything other than demonstration purposes,
476 * as it is neither a full nor a standards compliant implementation.
477 *
478 * <b>Non-USB Library Components</b>
479 * - The Serial_IsCharReceived() macro has been changed to the correct spelling of Serial_IsCharReceived() in Serial.h.
480 *
481 * <b>Device Mode</b>
482 * - The MANUAL_PLL_CONTROL compile time token has been removed, and replaced with a USB_OPT_MANUAL_PLL mask
483 * to be used in the Options parameter of the USB_Init() function.
484 * - Calling USB_Init() now forces a complete USB interface reset and enumeration, even if the USB interface is
485 * currently initialized.
486 * - Interrupts are now disabled when processing control requests, to avoid problems with interrupts causing the library
487 * or user request processing code to exceed the strict USB timing requirements on control transfers.
488 * - The USB Reset event now resets and disables all device endpoints. If user code depends on endpoints remaining configured
489 * after a Reset event, it should be altered to explicitly re-initialize all user endpoints.
490 * - The prototype for the GetDescriptor function has been changed, as the return value was redundant. The function now
491 * returns the size of the descriptor, rather than passing it back via a parameter, or returns NO_DESCRIPTOR if the specified
492 * descriptor does not exist.
493 * - The NO_DESCRIPTOR_STRING macro has been renamed NO_DESCRIPTOR, and is now also used as a possible return value for the
494 * GetDescriptor function.
495 *
496 * <b>Host Mode</b>
497 * - The MANUAL_PLL_CONTROL compile time token has been removed, and replaced with a USB_OPT_MANUAL_PLL mask
498 * to be used in the Options parameter of the USB_Init() function.
499 * - The HID report parser now supports multiple Report IDs. The HID report parser GetReportItemInfo() and
500 * SetReportItemInfo() routines now return a boolean, set if the requested report item was located in the
501 * current report. If sending a report to a multi-report device, the first byte of the report is automatically
502 * set to the report ID of the given report item.
503 * - Calling USB_Init() now forces a complete USB interface reset and enumeration, even if the USB interface is
504 * currently initialized.
505 *
506 * \section Sec_Migration152 Migrating from V1.5.2 to V1.5.3
507 *
508 * <b>Library Demos</b>
509 * - Previously, all demos contained a serial number string descriptor, filled with all zeros. A serial number
510 * string is required in Mass Storage devices, or devices which are to retain settings when moved between
511 * ports on a machine. As people were not changing the serial number value, this was causing conflicts and so
512 * the serial number descriptor has been removed from all but the Mass Storage demo, which requires it.
513 * - The AudioOut and AudioIn demos did not previously silence their endpoints when the host has deactivated
514 * them. Projects built upon either demo should upgrade to the latest code.
515 * - The FEATURE_ENDPOINT macro has been renamed FEATURE_ENDPOINT_HALT, and is now correctly documented.
516 * - The MassStoreHost demo contained errors which caused it to lock up randomly on certain devices. Projects built
517 * on the MassStoreDemo code should update to the latest version.
518 * - The Interrupt type endpoint in the CDC based demos previously had a polling interval of 0x02, which caused
519 * problems on some Linux systems. This has been changed to 0xFF, projects built on the CDC demos should upgrade
520 * to the latest code.
521 * - The HID keyboard and mouse demos were not previously boot mode compatible. To enable boot mode support, projects
522 * built on the keyboard or mouse demos (or derivatives) should upgrade to the latest code.
523 * - The Mass Storage demo was not previously standards compliant. Projects built on the Mass Storage demo should
524 * upgrade to the latest code.
525 * - The USART was not being reconfigured after the host sent new encoding settings in the USBtoSerial demo. This was
526 * previously discovered and fixed, but the change was lost. Projects built on the USBtoSerial demo should update
527 * to the latest code.
528 *
529 * <b>Device Mode</b>
530 * - The endpoint non-control stream functions now have a default timeout of 50ms between packets in the stream.
531 * If this timeout is exceeded, the function returns the new ENDPOINT_RWSTREAM_ERROR_Timeout error value. The
532 * timeout value can be overridden by defining the USB_STREAM_TIMEOUT_MS in the project makefile to the desired
533 * timeout duration in ms.
534 * - Rather than returning fixed values, the flags indicating if the device has Remote Wakeup currently enabled
535 * and/or is self-powered are now accessed and set through the new USB_RemoteWakeupEnabled and
536 * USB_CurrentlySelfPowered macros. See the DevChapter9.h documentation for more details.
537 * - All endpoint stream functions now require an extra Callback function parameter. Existing code may be updated
538 * to either supply NO_STREAM_CALLBACK as the extra parameter, or disable stream callbacks altogether by passing
539 * the token NO_STREAM_CALLBACKS to the compiler using the -D switch.
540 *
541 * <b>Host Mode</b>
542 * - The pipe non-control stream functions now have a default timeout of 50ms between packets in the stream.
543 * If this timeout is exceeded, the function returns the new PIPE_RWSTREAM_ERROR_Timeout error value. The
544 * timeout value can be overridden by defining the USB_STREAM_TIMEOUT_MS in the project makefile to the desired
545 * timeout duration in ms.
546 * - CollectionPath_t has been renamed to HID_CollectionPath_t to be more in line with the other HID parser structures.
547 * - All pipe stream functions now require an extra Callback function parameter. Existing code may be updated
548 * to either supply NO_STREAM_CALLBACK as the extra parameter, or disable stream callbacks altogether by passing
549 * the token NO_STREAM_CALLBACKS to the compiler using the -D switch.
550 *
551 * \section Sec_Migration151 Migrating from V1.5.1 to V1.5.2
552 *
553 * <b>Library Demos</b>
554 * - The RNDIS demo application has been updated so that it is functional on Linux under earlier implementations
555 * of the RNDIS specification, which had non-standard behaviour. Projects built upon the demo should upgrade
556 * to the latest code.
557 * - The DFU class bootloader has had several bugs corrected in this release. It is recommended that where
558 * possible any existing devices upgrade to the latest bootloader code.
559 *
560 * \section Sec_Migration150 Migrating from V1.5.0 to V1.5.1
561 *
562 * <b>Library Demos</b>
563 * - The USBtoSerial demo was broken in the 1.5.0 release, due to incorrect register polling in place of the
564 * global "Transmitting" flag. The change has been reverted in this release. Projects built upon the demo
565 * should upgrade to the latest code.
566 * - The HID class demos did not implement the mandatory GetReport HID class request. Projects built upon the HID
567 * demos should upgrade to the latest code.
568 * - The HID class demos incorrectly reported themselves as boot-protocol enabled HID devices in their descriptors.
569 * Projects built upon the HID demos should upgrade to the latest code.
570 * - The MIDI device demo had incorrect AudioStreaming interface descriptors. Projects built upon the MIDI demo
571 * should upgrade to the latest code.
572 * - The AudioOut demo did not correctly tristate the speaker pins when USB was disconnected, wasting power.
573 * Projects built upon the AudioOut demo should upgrade to the latest code.
574 *
575 * \section Sec_Migration141 Migrating from V1.4.1 to V1.5.0
576 *
577 * <b>Library Demos</b>
578 * - Previous versions of the library demos had incorrectly encoded BCD version numbers in the descriptors. To
579 * avoid such mistakes in the future, the VERSION_BCD macro has been added to StdDescriptors.h. Existing
580 * projects should at least manually correct the BCD version numbers, or preferably update the descriptors to
581 * encode the version number in BCD format using the new macro.
582 * - The mandatory GetReport class-specific request was accidentally omitted from previous versions of the demos
583 * based on the Human Interface Device (HID) class. This has been corrected, and any user projects based on the
584 * HID demos should also be updated accordingly.
585 * - The CDC demos now correctly send an empty packet directly after a full packet, to end the transmission.
586 * Failure to do this on projects which always or frequently send full packets will cause buffering issues on
587 * the host OS. All CDC user projects are advised to update their transmission routines in the same manner as
588 * the library CDC demos.
589 * - The previous interrupt-driven Endpoint/Pipe demos did not properly save and restore the currently selected
590 * Endpoint/Pipe when the ISR fired. This has been corrected - user projects based on the interrupt driven
591 * demos should also update to properly save and restore the selected Endpoint/Pipe.
592 *
593 * <b>Non-USB Library Components</b>
594 * - The Atomic.h and ISRMacro.h header files in MyUSB/Common have been removed, as the library is now only
595 * compatible with avr-libc library versions newer than the time before the functionality of the deleted
596 * headers was available.
597 *
598 * <b>Device Mode</b>
599 * - The GetDescriptor function (see StdDescriptors.h) now has a new prototype, with altered parameter names and
600 * functions. Existing projects will need to update the GetDescriptor implementation to reflect the new API.
601 * The previously split Type and Index parameters are now passed as the original wValue parameter to the
602 * function, to make way for the USB specification wIndex parameter which is <i>not</i> the same as the
603 * previous Index parameter.
604 * - The USB_UnhandledControlPacket event (see Events.h) now has new parameter names, to be in line with the
605 * official USB specification. Existing code will need to be altered to use the new parameter names.
606 * - The USB_CreateEndpoints event (see Events.h) has been renamed to USB_ConfigurationChanged, which is more
607 * appropriate. It fires in an identical manner to the previously named event, thus the only change to be made
608 * is the event name itself in the user project.
609 * - The USB_Descriptor_Language_t structure no longer exists in StdDescriptors.h, as this was a
610 * pseudo-descriptor modeled on the string descriptor. It is replaced by the true USB_Descriptor_String_t type
611 * descriptor as indicated in the USB specification, thus all device code must be updated accordingly.
612 * - The names of several Endpoint macros have been changed to be more consistent with the rest of the library,
613 * with no implementation changes. This means that existing code can be altered to use the new macro names
614 * with no other considerations required. See Endpoint.h for the new macro names.
615 * - The previous version of the MassStorage demo had an incorrect value in the SCSI_Request_Sense_Response_t
616 * structure named SenseData in SCSI.c which caused some problems with some hosts. User projects based on this
617 * demo should correct the structure value to maintain compatibility across multiple OS platforms.
618 * - By default, the descriptor structures use the official USB specification names for the elements. Previous
619 * versions of the library used non-standard (but more verbose) names, which are still usable in the current
620 * and future releases when the correct compile time option is enabled. See the StdDescriptors.h file
621 * documentation for more details.
622 *
623 * <b>Host Mode</b>
624 * - The USB_Host_Request_Header_t structure in HostChapter9.h (used for issuing control requests) has had its
625 * members renamed to the official USB specification names for requests. Existing code will need to be updated
626 * to use the new names.
627 * - The names of several Pipe macros have been changed to be more consistent with the rest of the library,
628 * with no implementation changes. This means that existing code can be altered to use the new macro names
629 * with no other considerations required. See Pipe.h for the new macro names.
630 * - By default, the descriptor structures use the official USB specification names for the elements. Previous
631 * versions of the library used non-standard (but more verbose) names, which are still usable in the current
632 * and future releases when the correct compile time option is enabled. See the StdDescriptors.h file
633 * documentation for more details.
634 * - The names of the macros in Host.h for controlling the SOF generation have been renamed, see the Host.h
635 * module documentation for the new macro names.
636 *
637 * <b>Dual Role Mode</b>
638 * - The OTG.h header file has been corrected so that the macros now perform their stated functions. Any existing
639 * projects using custom headers to fix the broken OTG header should now be altered to once again use the OTG
640 * header inside the library.
641 * - The USB_DeviceEnumerationComplete event (see Events.h) now also fires in Device mode, when the host has
642 * finished enumerating the device. Projects relying on the event only firing in Host mode should be updated
643 * so that the event action only occurs when the USB_Mode global is set to USB_MODE_HOST.
644 */
645