A USB Composite Device is a USB Device which uses more than one USB class.

In this use case, the "USB CDC (Composite Device)" module is used to create a USB composite device. Thus, this USB module can be associated with another "Composite Device" module, like "USB HID Mouse (Composite Device)".

Also, you can refer to application note AVR4902 ASF - USB Composite Device.

Setup Steps

For the setup code of this use case to work, the basic use case must be followed.

Usage Steps

Example Code

Content of conf_usb.h:

#define USB_DEVICE_EP_CTRL_SIZE  64
#define USB_DEVICE_NB_INTERFACE (X+2)
#define USB_DEVICE_MAX_EP (X+3)
#define  UDI_CDC_DATA_EP_IN_0          (1 | USB_EP_DIR_IN)  // TX
#define  UDI_CDC_DATA_EP_OUT_0         (2 | USB_EP_DIR_OUT) // RX
#define  UDI_CDC_COMM_EP_0             (3 | USB_EP_DIR_IN)  // Notify endpoint
#define  UDI_CDC_COMM_IFACE_NUMBER_0   X+0
#define  UDI_CDC_DATA_IFACE_NUMBER_0   X+1
#define UDI_COMPOSITE_DESC_T \
   usb_iad_desc_t udi_cdc_iad; \
   udi_cdc_comm_desc_t udi_cdc_comm; \
   udi_cdc_data_desc_t udi_cdc_data; \
   ...
#define UDI_COMPOSITE_DESC_FS \
   .udi_cdc_iad               = UDI_CDC_IAD_DESC_0, \
   .udi_cdc_comm              = UDI_CDC_COMM_DESC_0, \
   .udi_cdc_data              = UDI_CDC_DATA_DESC_0_FS, \
   ...
#define UDI_COMPOSITE_DESC_HS \
   .udi_cdc_iad               = UDI_CDC_IAD_DESC_0, \
   .udi_cdc_comm              = UDI_CDC_COMM_DESC_0, \
   .udi_cdc_data              = UDI_CDC_DATA_DESC_0_HS, \
   ...
#define UDI_COMPOSITE_API \
   &udi_api_cdc_comm,       \
   &udi_api_cdc_data,       \
   ...

Workflow

Ensure that conf_usb.h is available and contains the following parameters required for a USB composite device configuration:
- // Endpoint control size, This must be:
  
  // - 8, 16, 32 or 64 for full speed device (8 is recommended to save RAM)
  
  // - 64 for a high speed device
  
  #define USB_DEVICE_EP_CTRL_SIZE 64
  
  // Total Number of interfaces on this USB device.
  
  // Add 2 for CDC.
  
  #define USB_DEVICE_NB_INTERFACE (X+2)
  
  // Total number of endpoints on this USB device.
  
  // This must include each endpoint for each interface.
  
  // Add 3 for CDC.
  
  #define USB_DEVICE_MAX_EP (X+3)
Ensure that conf_usb.h contains the description of composite device:
- // The endpoint numbers chosen by you for the CDC.
  
  // The endpoint numbers starting from 1.
  
  #define UDI_CDC_DATA_EP_IN_0 (1 | USB_EP_DIR_IN) // TX
  
  #define UDI_CDC_DATA_EP_OUT_0 (2 | USB_EP_DIR_OUT) // RX
  
  #define UDI_CDC_COMM_EP_0 (3 | USB_EP_DIR_IN) // Notify endpoint
  
  // The interface index of an interface starting from 0
  
  #define UDI_CDC_COMM_IFACE_NUMBER_0 X+0
  
  #define UDI_CDC_DATA_IFACE_NUMBER_0 X+1
Ensure that conf_usb.h contains the following parameters required for a USB composite device configuration:
- // USB Interfaces descriptor structure
  
  #define UDI_COMPOSITE_DESC_T \
  
  ...
  
  usb_iad_desc_t udi_cdc_iad; \
  
  udi_cdc_comm_desc_t udi_cdc_comm; \
  
  udi_cdc_data_desc_t udi_cdc_data; \
  
  ...
  
  // USB Interfaces descriptor value for Full Speed
  
  #define UDI_COMPOSITE_DESC_FS \
  
  ...
  
  .udi_cdc_iad = UDI_CDC_IAD_DESC_0, \
  
  .udi_cdc_comm = UDI_CDC_COMM_DESC_0, \
  
  .udi_cdc_data = UDI_CDC_DATA_DESC_0_FS, \
  
  ...
  
  // USB Interfaces descriptor value for High Speed
  
  #define UDI_COMPOSITE_DESC_HS \
  
  ...
  
  .udi_cdc_iad = UDI_CDC_IAD_DESC_0, \
  
  .udi_cdc_comm = UDI_CDC_COMM_DESC_0, \
  
  .udi_cdc_data = UDI_CDC_DATA_DESC_0_HS, \
  
  ...
  
  // USB Interface APIs
  
  #define UDI_COMPOSITE_API \
  
  ...
  
  &udi_api_cdc_comm, \
  
  &udi_api_cdc_data, \
  
  ...
- Note
  The descriptors order given in the four lists above must be the same as the order defined by all interface indexes. The interface index orders are defined through UDI_X_IFACE_NUMBER defines.
  Also, the CDC requires a USB Interface Association Descriptor (IAD) for composite device.
  A USB Composite Device is a USB Device which uses more than one USB class.

In this use case, the "USB CDC (Composite Device)" module is used to create a USB composite device. Thus, this USB module can be associated with another "Composite Device" module, like "USB HID Mouse (Composite Device)".

Also, you can refer to application note AVR4902 ASF - USB Composite Device.

Setup Steps

For the setup code of this use case to work, the Basic Use Case must be followed.

Usage Steps

Example Code

Content of conf_usb.h:

#define USB_DEVICE_EP_CTRL_SIZE  64
#define USB_DEVICE_NB_INTERFACE (X+2)
#define USB_DEVICE_MAX_EP (X+3)
#define  UDI_CDC_DATA_EP_IN_0          (1 | USB_EP_DIR_IN)  // TX
#define  UDI_CDC_DATA_EP_OUT_0         (2 | USB_EP_DIR_OUT) // RX
#define  UDI_CDC_COMM_EP_0             (3 | USB_EP_DIR_IN)  // Notify endpoint
#define  UDI_CDC_COMM_IFACE_NUMBER_0   X+0
#define  UDI_CDC_DATA_IFACE_NUMBER_0   X+1
#define UDI_COMPOSITE_DESC_T \
   usb_iad_desc_t udi_cdc_iad; \
   udi_cdc_comm_desc_t udi_cdc_comm; \
   udi_cdc_data_desc_t udi_cdc_data; \
   ...
#define UDI_COMPOSITE_DESC_FS \
   .udi_cdc_iad               = UDI_CDC_IAD_DESC_0, \
   .udi_cdc_comm              = UDI_CDC_COMM_DESC_0, \
   .udi_cdc_data              = UDI_CDC_DATA_DESC_0_FS, \
   ...
#define UDI_COMPOSITE_DESC_HS \
   .udi_cdc_iad               = UDI_CDC_IAD_DESC_0, \
   .udi_cdc_comm              = UDI_CDC_COMM_DESC_0, \
   .udi_cdc_data              = UDI_CDC_DATA_DESC_0_HS, \
   ...
#define UDI_COMPOSITE_API \
   &udi_api_cdc_comm,       \
   &udi_api_cdc_data,       \
   ...

Workflow

Ensure that conf_usb.h is available and contains the following parameters required for a USB composite device configuration:
// Endpoint control size, This must be:

// - 8, 16, 32 or 64 for full speed device (8 is recommended to save RAM)

// - 64 for a high speed device

#define USB_DEVICE_EP_CTRL_SIZE 64

// Total Number of interfaces on this USB device.

// Add 2 for CDC.

#define USB_DEVICE_NB_INTERFACE (X+2)

// Total number of endpoints on this USB device.

// This must include each endpoint for each interface.

// Add 3 for CDC.

#define USB_DEVICE_MAX_EP (X+3)
Ensure that conf_usb.h contains the description of composite device:
// The endpoint numbers chosen by you for the CDC.

// The endpoint numbers starting from 1.

#define UDI_CDC_DATA_EP_IN_0 (1 | USB_EP_DIR_IN) // TX

#define UDI_CDC_DATA_EP_OUT_0 (2 | USB_EP_DIR_OUT) // RX

#define UDI_CDC_COMM_EP_0 (3 | USB_EP_DIR_IN) // Notify endpoint

// The interface index of an interface starting from 0

#define UDI_CDC_COMM_IFACE_NUMBER_0 X+0

#define UDI_CDC_DATA_IFACE_NUMBER_0 X+1
Ensure that conf_usb.h contains the following parameters required for a USB composite device configuration:
// USB Interfaces descriptor structure

#define UDI_COMPOSITE_DESC_T \

...

usb_iad_desc_t udi_cdc_iad; \

udi_cdc_comm_desc_t udi_cdc_comm; \

udi_cdc_data_desc_t udi_cdc_data; \

...

// USB Interfaces descriptor value for Full Speed

#define UDI_COMPOSITE_DESC_FS \

...

.udi_cdc_iad = UDI_CDC_IAD_DESC_0, \

.udi_cdc_comm = UDI_CDC_COMM_DESC_0, \

.udi_cdc_data = UDI_CDC_DATA_DESC_0_FS, \

...

// USB Interfaces descriptor value for High Speed

#define UDI_COMPOSITE_DESC_HS \

...

.udi_cdc_iad = UDI_CDC_IAD_DESC_0, \

.udi_cdc_comm = UDI_CDC_COMM_DESC_0, \

.udi_cdc_data = UDI_CDC_DATA_DESC_0_HS, \

...

// USB Interface APIs

#define UDI_COMPOSITE_API \

...

&udi_api_cdc_comm, \

&udi_api_cdc_data, \

...

Note
The descriptors order given in the four lists above must be the same as the order defined by all interface indexes. The interface index orders are defined through UDI_X_IFACE_NUMBER defines. Also, the CDC requires a USB Interface Association Descriptor (IAD) for composite device.

Microchip® Advanced Software Framework

Setup Steps

Usage Steps

Example Code

Workflow

Setup Steps

Usage Steps

Example Code

Workflow