USB Audio descriptors

nRF52840 only: Descriptors used in the USB Audio class. More...

Macros
#define	APP_USBD_AUDIO_INTERFACE_DSC(interface_number, alt_setting, ep_num, subclass)
	Initializer of interface descriptor for AUDIO class. More...
#define	APP_USBD_AUDIO_ISO_EP_DSC(ep, ep_size, interval, refresh, synch_addr)
	Initializer of isochronous endpoint descriptors for audio class. More...
#define	APP_USBD_AUDIO_ISO_EP_IN_DSC(ep_size)   APP_USBD_AUDIO_ISO_EP_DSC(NRF_DRV_USBD_EPIN8, ep_size, 1, 0, 0)
	Simplified version of APP_USBD_AUDIO_ISO_EP_DSC for ISO IN endpoint.
#define	APP_USBD_AUDIO_ISO_EP_OUT_DSC(ep_size)   APP_USBD_AUDIO_ISO_EP_DSC(NRF_DRV_USBD_EPOUT8, ep_size, 1, 0, 0)
	Simplified version of APP_USBD_AUDIO_ISO_EP_DSC for ISO OUT endpoint.
#define	APP_USBD_AUDIO_AC_IFACE_HEADER_DSC(descriptor_list,...)
	Initializer of app_usbd_audio_ac_iface_header_desc_t. More...
#define	APP_USBD_AUDIO_INPUT_TERMINAL_DSC(terminal_id, terminal_type, nr_channels, ch_config)
	Initializer of app_usbd_audio_input_terminal_desc_t. More...
#define	APP_USBD_AUDIO_OUTPUT_TERMINAL_DSC(terminal_id, terminal_type, source_id)
	Initializer of app_usbd_audio_output_terminal_desc_t. More...
#define	APP_USBD_AUDIO_FEATURE_UNIT_DSC(unit_id, source_id,...)
	Initializer of app_usbd_audio_feature_unit_desc_t. More...
#define	APP_USBD_AUDIO_AS_IFACE_DSC(terminal_link, delay, format_tag)
	Initializer of app_usbd_audio_as_iface_desc_t. More...
#define	APP_USBD_AUDIO_AS_FORMAT_I_DSC(nr_channels, subframe_size, resolution, freq_type,...)
	Initializer of app_usbd_audio_as_format_type_one_desc_t. More...
#define	APP_USBD_AUDIO_AS_FORMAT_II_DSC(max_bitrate, samples_per_frame, freq_type,...)
	Initializer of app_usbd_audio_as_format_type_two_desc_t. More...
#define	APP_USBD_AUDIO_AS_FORMAT_III_DSC(nr_channels, subframe_size, resolution, freq_type,...)
	Initializer of app_usbd_audio_as_format_type_three_desc_t. More...
#define	APP_USBD_AUDIO_EP_GENERAL_DSC(attributes, lock_delay_units, lock_delay)
	Initializer of app_usbd_audio_as_endpoint_desc_t. More...
#define	APP_USBD_AUDIO_CONTROL_DSC(interface_number, descriptor_list, interface_list)
	Macro to configure Audio Class control descriptor. More...
#define	APP_USBD_AUDIO_STREAMING_DSC(interface_number, alt_setting, ep_num)
	Macro to configure Audio Class streaming descriptor. More...
#define	APP_USBD_AUDIO_MIDI_STREAMING_DSC(interface_number, alt_setting, ep_num)
	Macro to configure Audio Class MIDI streaming descriptor. More...

Detailed Description

nRF52840 only: Descriptors used in the USB Audio class.

Macro Definition Documentation

#define APP_USBD_AUDIO_AC_IFACE_HEADER_DSC	(		descriptor_list,
			...
	)

Value:

/*.bLength = */ sizeof(app_usbd_audio_ac_iface_header_desc_t) + \
 (NUM_VA_ARGS(__VA_ARGS__)), \
 /*.bDescriptorType = */ APP_USBD_AUDIO_DESCRIPTOR_INTERFACE, \
 /*.bDescriptorSubtype = */ APP_USBD_AUDIO_AC_IFACE_SUBTYPE_HEADER, \
 /*.bcdADC = */ APP_USBD_U16_TO_RAW_DSC(0x0100), \
 /*.wTotalLength = */ APP_USBD_U16_TO_RAW_DSC( \
 sizeof((uint8_t[]){BRACKET_EXTRACT(descriptor_list)}) + \
 sizeof(app_usbd_audio_ac_iface_header_desc_t) + \
 (NUM_VA_ARGS(__VA_ARGS__))), \
 /*.bInCollection = */ (NUM_VA_ARGS(__VA_ARGS__)), \
 /*.baInterfaceNr[] = */ __VA_ARGS__, \

Initializer of app_usbd_audio_ac_iface_header_desc_t.

Parameters

descriptor_list	Descriptor list following audio interface header descriptor.
...	List of interfaces following audio control interface.

#define APP_USBD_AUDIO_AS_FORMAT_I_DSC	(		nr_channels,
			subframe_size,
			resolution,
			freq_type,
			...
	)

Value:

/*.bLength = */ sizeof(app_usbd_audio_as_format_type_one_desc_t) + \
 (NUM_VA_ARGS(__VA_ARGS__)), \
 /*.bDescriptorType = */ APP_USBD_AUDIO_DESCRIPTOR_INTERFACE, \
 /*.bDescriptorSubtype = */ APP_USBD_AUDIO_AS_IFACE_SUBTYPE_FORMAT_TYPE, \
 /*.bFormatType = */ (1), \
 /*.bNrChannels = */ (nr_channels), \
 /*.bSubFrameSize = */ (subframe_size), \
 /*.bBitResolution = */ (resolution), \
 /*.bSamFreqType = */ (freq_type), \
 /*.tSamFreq = */ __VA_ARGS__, \

Initializer of app_usbd_audio_as_format_type_one_desc_t.

Parameters

nr_channels	Number of channels.
subframe_size	Subframe size.
resolution	Bit resolution.
freq_type	Frequency type.
...	List of frequencies.

#define APP_USBD_AUDIO_AS_FORMAT_II_DSC	(		max_bitrate,
			samples_per_frame,
			freq_type,
			...
	)

Value:

/*.bLength = */ sizeof(app_usbd_audio_as_format_type_two_desc_t) + \
 (NUM_VA_ARGS(__VA_ARGS__)), \
 /*.bDescriptorType = */ APP_USBD_AUDIO_DESCRIPTOR_INTERFACE, \
 /*.bDescriptorSubtype = */ APP_USBD_AUDIO_AS_IFACE_SUBTYPE_FORMAT_TYPE, \
 /*.bFormatType = */ (2), \
 /*.wMaxBitRate = */ APP_USBD_U16_TO_RAW_DSC(max_bitrate), \
 /*.wSamplesPerFrame = */ APP_USBD_U16_TO_RAW_DSC(samples_per_frame), \
 /*.bSamFreqType = */ (freq_type), \
 /*.tSamFreq = */ __VA_ARGS__, \

Initializer of app_usbd_audio_as_format_type_two_desc_t.

Parameters

max_bitrate	Maximum bitrate.
samples_per_frame	Samples per frame.
freq_type	Frequency type.
...	List of frequencies.

#define APP_USBD_AUDIO_AS_FORMAT_III_DSC	(		nr_channels,
			subframe_size,
			resolution,
			freq_type,
			...
	)

Value:

/*.bLength = */ sizeof(app_usbd_audio_as_format_type_three_desc_t) + \
 (NUM_VA_ARGS(__VA_ARGS__)), \
 /*.bDescriptorType = */ APP_USBD_AUDIO_DESCRIPTOR_INTERFACE, \
 /*.bDescriptorSubtype = */ APP_USBD_AUDIO_AS_IFACE_SUBTYPE_FORMAT_TYPE, \
 /*.bFormatType = */ (3), \
 /*.bNrChannels = */ (nr_channels), \
 /*.bSubFrameSize = */ (subframe_size), \
 /*.bBitResolution = */ (resolution), \
 /*.bSamFreqType = */ (freq_type), \
 /*.tSamFreq = */ __VA_ARGS__, \

Initializer of app_usbd_audio_as_format_type_three_desc_t.

Parameters

nr_channels	Number of channels.
subframe_size	Subframe size.
resolution	Bit resolution.
freq_type	Frequency type.
...	List of frequencies.

#define APP_USBD_AUDIO_AS_IFACE_DSC	(		terminal_link,
			delay,
			format_tag
	)

Value:

/*.bLength = */ sizeof(app_usbd_audio_as_iface_desc_t), \
 /*.bDescriptorType = */ APP_USBD_AUDIO_DESCRIPTOR_INTERFACE, \
 /*.bDescriptorSubtype = */ APP_USBD_AUDIO_AS_IFACE_SUBTYPE_GENERAL, \
 /*.bTerminalLink = */ (terminal_link), \
 /*.bDelay = */ (delay), \
 /*.wFormatTag = */ APP_USBD_U16_TO_RAW_DSC(format_tag), \

Initializer of app_usbd_audio_as_iface_desc_t.

Parameters

terminal_link	Terminal link.
delay	Delay.
format_tag	Format TAG.

#define APP_USBD_AUDIO_CONTROL_DSC	(		interface_number,
			descriptor_list,
			interface_list
	)

Value:

APP_USBD_AUDIO_INTERFACE_DSC(interface_number, 0, 0, APP_USBD_AUDIO_SUBCLASS_AUDIOCONTROL) \
 APP_USBD_AUDIO_AC_IFACE_HEADER_DSC(descriptor_list, BRACKET_EXTRACT(interface_list)) \
 BRACKET_EXTRACT(descriptor_list)

Macro to configure Audio Class control descriptor.

Parameters

interface_number	Interface number.
descriptor_list	List of descriptors after Audio interface header descriptor.
interface_list	List of interfaces passed to APP_USBD_AUDIO_AC_IFACE_HEADER_DSC

#define APP_USBD_AUDIO_EP_GENERAL_DSC	(		attributes,
			lock_delay_units,
			lock_delay
	)

Value:

/*.bLength = */ sizeof(app_usbd_audio_as_endpoint_desc_t), \
 /*.bDescriptorType = */ APP_USBD_AUDIO_DESCRIPTOR_ENDPOINT, \
 /*.bDescriptorSubtype = */ APP_USBD_AUDIO_EP_SUBTYPE_GENERAL, \
 /*.bmAttributes = */ (attributes), \
 /*.bLockDelayUnits = */ (lock_delay_units), \
 /*.wLockDelay = */ APP_USBD_U16_TO_RAW_DSC(lock_delay), \

Initializer of app_usbd_audio_as_endpoint_desc_t.

Parameters

attributes	Endpoint attributes.
lock_delay_units	Lock delay units.
lock_delay	Lock delay.

#define APP_USBD_AUDIO_FEATURE_UNIT_DSC	(		unit_id,
			source_id,
			...
	)

Value:

/*.bLength = */ sizeof(app_usbd_audio_feature_unit_desc_t) + \
 1 + (NUM_VA_ARGS(__VA_ARGS__)), \
 /*.bDescriptorType = */ APP_USBD_AUDIO_DESCRIPTOR_INTERFACE, \
 /*.bDescriptorSubtype = */ APP_USBD_AUDIO_AC_IFACE_SUBTYPE_FEATURE_UNIT, \
 /*.bUnitID = */ (unit_id), \
 /*.bSourceID = */ (source_id), \
 /*.bControlSize = */ sizeof(uint16_t), \
 /*.bmaControls[] = */ __VA_ARGS__, \
 /*.iFeature = */ 0, \

Initializer of app_usbd_audio_feature_unit_desc_t.

Parameters

unit_id	Unit ID.
source_id	Source ID.
...	List of controls.

#define APP_USBD_AUDIO_INPUT_TERMINAL_DSC	(		terminal_id,
			terminal_type,
			nr_channels,
			ch_config
	)

Value:

/*.bLength = */ sizeof(app_usbd_audio_input_terminal_desc_t), \
 /*.bDescriptorType = */ APP_USBD_AUDIO_DESCRIPTOR_INTERFACE, \
 /*.bDescriptorSubtype = */ APP_USBD_AUDIO_AC_IFACE_SUBTYPE_INPUT_TERMINAL, \
 /*.bTerminalID = */ (terminal_id), \
 /*.wTerminalType = */ APP_USBD_U16_TO_RAW_DSC(terminal_type), \
 /*.bAssocTerminal = */ 0, \
 /*.bNrChannels = */ (nr_channels), \
 /*.wChannelConfig = */ APP_USBD_U16_TO_RAW_DSC(ch_config), \
 /*.iChannelNames = */ 0, \
 /*.iTerminal = */ 0, \

Initializer of app_usbd_audio_input_terminal_desc_t.

Parameters

terminal_id	Terminal ID.
terminal_type	Terminal type app_usbd_audio_terminal_type_t
nr_channels	Number of channels.
ch_config	Channel config bitmask.

#define APP_USBD_AUDIO_INTERFACE_DSC	(		interface_number,
			alt_setting,
			ep_num,
			subclass
	)

Value:

/*.bLength = */ sizeof(app_usbd_descriptor_iface_t), \
 /*.bDescriptorType = */ APP_USBD_DESCRIPTOR_INTERFACE, \
 /*.bInterfaceNumber = */ (interface_number), \
 /*.bAlternateSetting = */ (alt_setting), \
 /*.bNumEndpoints = */ (ep_num), \
 /*.bInterfaceClass = */ APP_USBD_AUDIO_CLASS, \
 /*.bInterfaceSubClass = */ (subclass), \
 /*.bInterfaceProtocol = */ APP_USBD_AUDIO_CLASS_PROTOCOL_UNDEFINED, \
 /*.iInterface = 0, */ 0x00, \

Initializer of interface descriptor for AUDIO class.

Parameters

interface_number	Interface number.
alt_setting	Interface alternate setting.
ep_num	Number of endpoints.
subclass	Audio subclass app_usbd_audio_subclass_t

#define APP_USBD_AUDIO_ISO_EP_DSC	(		ep,
			ep_size,
			interval,
			refresh,
			synch_addr
	)

Value:

/*.bLength = */ sizeof(app_usbd_descriptor_ep_t) + 2, \
 /*.bDescriptorType = */ APP_USBD_DESCRIPTOR_ENDPOINT, \
 /*.bEndpointAddress = */ ep, \
 /*.bmAttributes = */ APP_USBD_DESCRIPTOR_EP_ATTR_TYPE_ISOCHRONOUS, \
 /*.wMaxPacketSize = */ APP_USBD_U16_TO_RAW_DSC(ep_size), \
 /*.bInterval = */ (interval), \
 /*.bRefresh = */ (refresh), \
 /*.bInterval = */ (synch_addr), \

Initializer of isochronous endpoint descriptors for audio class.

Parameters

ep	ISO endpoint id: NRF_DRV_USBD_EPIN8, NRF_DRV_USBD_EPOUT8
ep_size	Endpoint size (bytes).
interval	Endpoint interval (milliseconds).
refresh	Refresh value (usually 0).
synch_addr	Synch address (usually 0).

#define APP_USBD_AUDIO_MIDI_STREAMING_DSC	(		interface_number,
			alt_setting,
			ep_num
	)

Value:

APP_USBD_AUDIO_INTERFACE_DSC(interface_number, alt_setting, ep_num, \
 APP_USBD_AUDIO_SUBCLASS_MIDISTREAMING)

Macro to configure Audio Class MIDI streaming descriptor.

Parameters

interface_number	Interface number.
alt_setting	Alternate interface setting.
ep_num	Number of endpoints.

#define APP_USBD_AUDIO_OUTPUT_TERMINAL_DSC	(		terminal_id,
			terminal_type,
			source_id
	)

Value:

/*.bLength = */ sizeof(app_usbd_audio_output_terminal_desc_t), \
 /*.bDescriptorType = */ APP_USBD_AUDIO_DESCRIPTOR_INTERFACE, \
 /*.bDescriptorSubtype = */ APP_USBD_AUDIO_AC_IFACE_SUBTYPE_OUTPUT_TERMINAL, \
 /*.bTerminalID = */ (terminal_id), \
 /*.wTerminalType = */ APP_USBD_U16_TO_RAW_DSC(terminal_type), \
 /*.bAssocTerminal = */ 0, \
 /*.bSourceID = */ (source_id), \
 /*.iTerminal = */ 0, \

Initializer of app_usbd_audio_output_terminal_desc_t.

Parameters

terminal_id	Terminal ID.
terminal_type	Terminal type app_usbd_audio_terminal_type_t
source_id	Source ID.

#define APP_USBD_AUDIO_STREAMING_DSC	(		interface_number,
			alt_setting,
			ep_num
	)

Value:

APP_USBD_AUDIO_INTERFACE_DSC(interface_number, alt_setting, ep_num, \
 APP_USBD_AUDIO_SUBCLASS_AUDIOSTREAMING)

Macro to configure Audio Class streaming descriptor.

Parameters

interface_number	Interface number.
alt_setting	Alternate interface setting.
ep_num	Number of endpoints.