USB Device high level library

nRF52840 only: Module for easy support for any USB device configuration. More...

Modules
	USBD Class Base module
	nRF52840 only: The base for any class instance is defined in this module.
	USB Device high level library core module
	nRF52840 only: Core module that manages current USB state and process device requests.
	USB standard descriptors
	nRF52840 only: Module with types definitions used for standard descriptors.
	USB Device library configuration
	USB standard requests
	nRF52840 only: Module with types definitions used for standard requests processing.
	USBD string descriptors
	nRF52840 only: USBD string descriptors management.
	USB Device high level library variable types definition
	nRF52840 only: All types used by USB Device high level library are defined here. This helps to avoid cross referencing into types in different files.
	USB AUDIO class
	nRF52840 only: Module with types, definitions, and API used by USB Audio class.
	USB CDC ACM class
	nRF52840 only: Module with types, definitions and API used by CDC ACM class.
	USB HID class
	nRF52840 only: Module with generic HID event data processing.
	USB MSC class
	nRF52840 only: Module with types, definitions, and API used by the USB MSC class.

Data Structures
struct	app_usbd_config_t
	Configuration passed to app_usbd_init. More...

Functions
ret_code_t	app_usbd_init (app_usbd_config_t const *p_config)
	USB library initialization. More...
ret_code_t	app_usbd_uninit (void)
	USB library un-initialization. More...
void	app_usbd_enable (void)
	Enable USBD. More...
void	app_usbd_disable (void)
	Disable USBD. More...
void	app_usbd_start (void)
	Request USBD to start. More...
void	app_usbd_stop (void)
	Stop USB to work. More...
void	app_usbd_suspend_req (void)
	Request library to suspend. More...
bool	app_usbd_wakeup_req (void)
	Request library to wake-up. More...
void	app_usbd_event_execute (app_usbd_internal_evt_t const *const p_event)
	USBD event processor. More...
bool	app_usbd_event_queue_process (void)
	Function that process events from the queue. More...
ret_code_t	app_usbd_class_append (app_usbd_class_inst_t const *p_cinst)
	Add class instance. More...
ret_code_t	app_usbd_class_remove (app_usbd_class_inst_t const *p_cinst)
	Remove class instance. More...
ret_code_t	app_usbd_class_remove_all (void)
	Remove all class instances. More...
ret_code_t	app_usbd_ep_handler_set (app_usbd_class_inst_t const *p_cinst, nrf_drv_usbd_ep_t ep, app_usbd_ep_event_handler_t handler)
	Change endpoint handler. More...
ret_code_t	app_usbd_class_sof_register (app_usbd_class_inst_t const *p_cinst)
	Register class instance as the one that requires SOF events. More...
ret_code_t	app_usbd_class_sof_unregister (app_usbd_class_inst_t const *p_cinst)
	Unregister class instance from SOF processing instances list. More...
ret_code_t	app_usbd_class_rwu_register (app_usbd_class_inst_t const *const p_inst)
	Register class on remote wake-up feature. More...
ret_code_t	app_usbd_class_rwu_unregister (app_usbd_class_inst_t const *const p_inst)
	Unregister class from remote wake-up feature. More...
bool	app_usbd_class_rwu_enabled_check (void)
	Check if there is any class with remote wakeup. More...
const void *	app_usbd_class_descriptor_find (app_usbd_class_inst_t const *const p_cinst, uint8_t desc_type, uint8_t desc_index, size_t *p_desc_len)
	Function finds a given descriptor type in class descriptors payload. More...
ret_code_t	app_usbd_interface_std_req_handle (app_usbd_setup_evt_t const *p_setup_ev)
	Standard interface request handle. More...
ret_code_t	app_usbd_endpoint_std_req_handle (app_usbd_setup_evt_t const *p_setup_ev)
	Standard endpoint request handle. More...
ret_code_t	app_usbd_req_std_set_interface (app_usbd_class_inst_t const *const p_cinst, app_usbd_setup_evt_t const *const p_setup_ev)
	Standard interface set request handle. More...

Iterate through classes lists
Functions that helps to iterate through internally chained classes.
app_usbd_class_inst_t const *	app_usbd_class_first_get (void)
	Get first class instance in the list. More...
static app_usbd_class_inst_t const *	app_usbd_class_next_get (app_usbd_class_inst_t const *const p_cinst)
	Get next instance in the list. More...
app_usbd_class_inst_t const *	app_usbd_class_sof_first_get (void)
	Get first instance in SOF list. More...
static app_usbd_class_inst_t const *	app_usbd_class_sof_next_get (app_usbd_class_inst_t const *const p_cinst)
	Get next instance in the SOF list. More...

Communicate with interfaces, endpoints and instances inside usbd library
ret_code_t	app_usbd_iface_call (uint8_t iface, app_usbd_complex_evt_t const *const p_event)
	Call interface event handler. More...
ret_code_t	app_usbd_ep_call (nrf_drv_usbd_ep_t ep, app_usbd_complex_evt_t const *const p_event)
	Call endpoint event handler. More...
void	app_usbd_all_call (app_usbd_complex_evt_t const *const p_event)
	Auxiliary function that process event by every instance in the list. More...
ret_code_t	app_usbd_all_until_served_call (app_usbd_complex_evt_t const *const p_event)
	Call interface event handlers and stop when served. More...

Detailed Description

nRF52840 only: Module for easy support for any USB device configuration.

This module manages class instances that would create the USB device, manages endpoints and interfaces transactions.

Function Documentation

void app_usbd_all_call

(

app_usbd_complex_evt_t const *const

p_event

)

Auxiliary function that process event by every instance in the list.

This function ignores the result of called handler.

Parameters

p_event

Event to pass to every instance

ret_code_t app_usbd_all_until_served_call

(

app_usbd_complex_evt_t const *const

p_event

)

Call interface event handlers and stop when served.

Call event handlers from instances as long as we get result different than NRF_ERROR_NOT_SUPPORTED

Parameters

[in]

p_event

Event structure to send

Returns

Operation status or NRF_ERROR_NOT_SUPPORTED if none of instances in the list can support given event.

ret_code_t app_usbd_class_append

(

app_usbd_class_inst_t const *

p_cinst

)

Add class instance.

This function connects given instance into internal class instance chain and into all required endpoints. The instance event handler would be connected into endpoint by default, but this can be overwritten by app_usbd_ep_handler_set.

After successful attachment APP_USBD_EVT_INST_APPEND would be passed to class instance.

Note

This function can only be called after USBD library is initialized but still disabled. Assertion would be generated otherwise.

Parameters

[in,out]

p_cinst

Instance to connect. Chain data would be written into writable instance data.

const void* app_usbd_class_descriptor_find	(	app_usbd_class_inst_t const *const	p_cinst,
		uint8_t	desc_type,
		uint8_t	desc_index,
		size_t *	p_desc_len
	)

Function finds a given descriptor type in class descriptors payload.

Parameters

[in]	p_cinst	Instance of a class
[in]	desc_type	Descriptor type (APP_USBD_SETUP_STDREQ_GET_DESCRIPTOR)
[in]	desc_index	Descriptor index (APP_USBD_SETUP_STDREQ_GET_DESCRIPTOR)
[out]	p_desc_len	Descriptor length

Returns

Address of the descriptor (NULL if not found)

app_usbd_class_inst_t const* app_usbd_class_first_get

(

void

)

Get first class instance in the list.

Get first instance from the list of active class instances. That instance may be used then in app_usbd_class_next_get function.

Returns

First instance in the list or NULL if there are no instances available.

static app_usbd_class_inst_t const* app_usbd_class_next_get ( app_usbd_class_inst_t const *const  p_cinst )

inlinestatic

Get next instance in the list.

Get the next instance from the list of active instances. Used to iterate through all instances.

Parameters

[in]

p_cinst

The current instance from with next one is required.

Returns

Next instance to the given one or NULL if there is no more instances in the list.

ret_code_t app_usbd_class_remove

(

app_usbd_class_inst_t const *

p_cinst

)

Remove class instance.

Instance is removed from instance chain. Instance and event handlers are removed also from endpoints. Endpoints used by by the class instance are left disabled.

Note

This function can only be called after USBD library is initialized but still disabled. Assertion would be generated otherwise.

Parameters

p_cinst

Instance pointer to remove.

Return values

NRF_SUCCESS	Instance successfully removed.
NRF_ERROR_NOT_FOUND	Instance not found in the instance chain.

ret_code_t app_usbd_class_remove_all

(

void

)

Remove all class instances.

This function basically calls app_usbd_class_remove on instances chain as long as there is any element left.

Note

This function can only be called after USBD library is initialized but still disabled. Assertion would be generated otherwise.

See Also

app_usbd_class_remove

Returns

Is should always return NRF_SUCCESS. Any error value returned would mean there is an error inside the library.

bool app_usbd_class_rwu_enabled_check

(

void

)

Check if there is any class with remote wakeup.

The function checks internal registered class with remote wakeup counter.

See Also

app_usbd_class_rwu_register, app_usbd_class_rwu_unregister

Return values

true	The remote wakeup functionality is required by some class instance
false	There is no class instance that requires wakeup functionality

ret_code_t app_usbd_class_rwu_register

(

app_usbd_class_inst_t const *const

p_inst

)

Register class on remote wake-up feature.

Parameters

[in]

p_inst

Instance of the class

Return values

NRF_SUCCESS

Instance that requires remote wake-up registered

ret_code_t app_usbd_class_rwu_unregister

(

app_usbd_class_inst_t const *const

p_inst

)

Unregister class from remote wake-up feature.

Parameters

[in]

p_inst

Instance of the class

Return values

NRF_SUCCESS

Instance that requires remote wake-up removed

app_usbd_class_inst_t const* app_usbd_class_sof_first_get

(

void

)

Get first instance in SOF list.

Start iteration through the list of instances that requires SOF event processing.

Returns

First instance in the list or NULL if the list is empty

See Also

app_usbd_class_first_get

static app_usbd_class_inst_t const* app_usbd_class_sof_next_get ( app_usbd_class_inst_t const *const  p_cinst )

inlinestatic

Get next instance in the SOF list.

Get the next instance from the list of instances requiring SOF event processing. Used to iterate through all SOF instances.

Parameters

p_cinst

The current instance from with next one is required.

Returns

Next instance to the given one or NULL if there is no more instances in the list.

ret_code_t app_usbd_class_sof_register

(

app_usbd_class_inst_t const *

p_cinst

)

Register class instance as the one that requires SOF events.

This function should be called in reaction on APP_USBD_EVT_INST_APPEND event. Connect the class instance to the list of instances that requires SOF processing. If none of the appended instances requires SOF event - it is disabled.

Parameters

p_cinst

Instance that requires SOF event.

Return values

NRF_SUCCESS

Instance linked into SOF processing list.

See Also

app_usbd_class_sof_unregister

ret_code_t app_usbd_class_sof_unregister

(

app_usbd_class_inst_t const *

p_cinst

)

Unregister class instance from SOF processing instances list.

Every class that calls app_usbd_class_sof_register have to call also unregistering function in reaction to APP_USBD_EVT_INST_REMOVE event.

Parameters

p_cinst

Instance to be unregistered from SOF event processing list.

Return values

NRF_SUCCESS	Instance linked into SOF processing list.
NRF_ERROR_NOT_FOUND	Instance not found in the SOF processing list.

See Also

app_usbd_class_sof_register

void app_usbd_disable

(

void

)

Disable USBD.

Disabled USDB peripheral cannot be accessed but also stops requesting High Frequency clock and releases power regulator.

Note

This function cannot be called when USB is started. Stop it first.

void app_usbd_enable

(

void

)

Enable USBD.

USBD is enabled. Since now the high frequency clock may be requested when USB RESET would be detected.

ret_code_t app_usbd_endpoint_std_req_handle

(

app_usbd_setup_evt_t const *

p_setup_ev

)

Standard endpoint request handle.

Parameters

[in]

p_setup_ev

Setup event

Returns

Standard error code

ret_code_t app_usbd_ep_call	(	nrf_drv_usbd_ep_t	ep,
		app_usbd_complex_evt_t const *const	p_event
	)

Call endpoint event handler.

Call event handler for the selected endpoint.

Parameters

[in]	ep	Endpoint number
[in]	p_event	Event structure to send

Returns

Operation status

ret_code_t app_usbd_ep_handler_set	(	app_usbd_class_inst_t const *	p_cinst,
		nrf_drv_usbd_ep_t	ep,
		app_usbd_ep_event_handler_t	handler
	)

Change endpoint handler.

This function may be called for the endpoint only if the class instance is already properly attached by the app_usbd_class_append function.

The endpoint event handler function can be only overwritten by the class instance that was connected into the endpoint.

Note

This function can only be called after USBD library is initialized but still disabled. Assertion would be generated otherwise.

Parameters

[in]	p_cinst	Instance of a class that wish to set new event handler. It has to match currently configured instance for the selected endpoint. In other situation error would be returned.
[in]	ep	Endpoint address to configure.
[in]	handler	Event handler function to set.

Return values

NRF_SUCCESS	New handler successfully set
NRF_ERROR_INVALID_PARAM	p_cinst is not the same as currently set for the endpoint

void app_usbd_event_execute

(

app_usbd_internal_evt_t const *const

p_event

)

USBD event processor.

Function to be called on each event to be processed by the library.

bool app_usbd_event_queue_process

(

void

)

Function that process events from the queue.

Note

This function calls app_usbd_event_execute internally.

Return values

true	Event was processed
false	The event queue is empty

ret_code_t app_usbd_iface_call	(	uint8_t	iface,
		app_usbd_complex_evt_t const *const	p_event
	)

Call interface event handler.

Call event handler for selected interface.

Parameters

[in]	iface	Target interface number
[in]	p_event	Event structure to send

Returns

Operation status

ret_code_t app_usbd_init

(

app_usbd_config_t const *

p_config

)

USB library initialization.

Call this function before any configuration or class attachment. USBD peripheral would be ready to accept commands, and library would be ready, but it would not be connected to the bus. Call app_usbd_enable to enable USBD communication with the host.

Parameters

p_config

Configuration. NULL pointer might be passed here and default configuration will be applied then.

ret_code_t app_usbd_interface_std_req_handle

(

app_usbd_setup_evt_t const *

p_setup_ev

)

Standard interface request handle.

Parameters

[in]

p_setup_ev

Setup event

Returns

Standard error code

ret_code_t app_usbd_req_std_set_interface	(	app_usbd_class_inst_t const *const	p_cinst,
		app_usbd_setup_evt_t const *const	p_setup_ev
	)

Standard interface set request handle.

Parameters

[in]	p_cinst	Instance of a class
[in]	p_setup_ev	Setup event

Returns

Standard error code

void app_usbd_start

(

void

)

Request USBD to start.

The function sends start request to the event queue. If the queue is enabled (APP_USBD_EVENT_QUEUE_ENABLE) it would be processed when the queue is processed. If queue is disabled it would be processed immediately inside this function. It means that if queue is disabled this function cannot be called from interrupt with priority higher than USB interrupt.

When start is processed it would:

1. Start library.
2. Enable interrupts.
3. Enable USB pull-ups.

Note

In some specific circumstances the library can be left not started and this function would silently exit. This may happen if some glitches appears on USB power line or if the plug was disconnected before whole starting process finishes. User would get the event from POWER peripheral then. Also no APP_USBD_EVT_STARTED event would be generated to the classes and user event handler. For the safe code it is recommended to wait for APP_USBD_EVT_STARTED event if anything has to be initialized after USB driver is started (just before enabling the interrupts). If library is properly started the APP_USBD_EVT_STARTED event passed to the user handler from this function body.

void app_usbd_stop

(

void

)

Stop USB to work.

The function sends stop request to the event queue. If the queue is enabled (APP_USBD_EVENT_QUEUE_ENABLE) it would be processed when the queue is processed. If queue is disabled it would be processed immediately inside this function. It means that if queue is disabled this function cannot be called from interrupt with priority higher than USB interrupt.

When the event is processed interrupts and USB pull-ups are disabled. The peripheral itself is left enabled so it can be programmed, but a HOST sees it as a peripheral disconnection.

Note

If the library is not started when this function is called it exits silently - also no APP_USBD_EVT_STOPPED is generated.

void app_usbd_suspend_req

(

void

)

Request library to suspend.

This function send suspend request to the event queue.

Note

This function should only be called after APP_USBD_EVT_DRV_SUSPEND os received. Internal suspend request processing would give no effect if the bus is not in suspend state.

ret_code_t app_usbd_uninit

(

void

)

USB library un-initialization.

Note

Currently not supported

bool app_usbd_wakeup_req

(

void

)

Request library to wake-up.

This function send wakeup request to the event queue.

Note

Calling this function does not mean that peripheral is active - the wakeup request is sent into message queue and needs to be processed.

Return values

true	Wakeup generation has been started.
false	No wakeup would be generated becouse it is disabled by the host.