Application template

The redesigned USB stack makes the composite device application easy to implement and aligned with the general device.

Application structure template

For a general device, a demo contains only one class. However, for the composite device, a demo contains more than one class. Likewise, a structure is required to manage the application involving more than one class.

typedef struct composite_device_struct
{
    usb_device_handle                  deviceHandle;
    class_handle_t                     classHandle1;
    class_handle_t                     classHandle2;
    …
    class_handle_t                     classHandlen;
    uint8_t                            speed;
    uint8_t                            attach;
    uint8_t                            currentConfiguration;
    uint8_t                            currentInterfaceAlternateSetting[USB_COMPOSITE_INTERFACE_COUNT];
}composite_device_struct_t;

deviceHandle: The handle pointer to a device, which is returned by the USB_DeviceClassInit.

speed: Speed of the USB device. USB_SPEED_FULL/USB_SPEED_LOW/USB_SPEED_HIGH.

attach: Indicates whether the device is attached or not.

currentConfiguration: The current device configuration value.

currentInterfaceAlternateSetting: The current alternate setting for each interface.

classHandlen: The pointer to a class.

This is an example for a composite device HID mouse + HID keyboard:

This structure is in the “composite.h” file.

Prototype:

typedef struct _usb_device_composite_struct
{
    usb_device_handle                  deviceHandle;
    class_handle_t                     hidMouseHandle;
    class_handle_t                     hidKeyboardHandle;
    uint8_t                            speed;
    uint8_t                            attach;
    uint8_t                            currentConfiguration;
    uint8_t                            currentInterfaceAlternateSetting[USB_COMPOSITE_INTERFACE_COUNT];
} usb_device_composite_struct_t;

Parent topic:Application template

Application initialization process

1. Before initializing the USB stack by calling the USB_DeviceClassInit function, the usb_device_class_config_list_struct_t and usb_device_class_config_struct_t are assigned values respectively. For example, for MSC + CDC, the steps are as follows:

   • Declare the g_compositeDeviceConfigList as global variables of the type usb_device_class_config_list_struct_t.

     usb_device_class_config_list_struct_t g_compositeDeviceConfigList =
     {
         g_compositeDevice,
         USB_DeviceCallback,
         2,
     };
     
     

   • Declare the g_compositeDevice as global variables of the type usb_device_class_config_struct_t.

     usb_device_class_config_struct_t g_compositeDevice[2] =
     {
         {
             USB_DeviceCdcVcomCallback,
             (class_handle_t)NULL,
             &g_UsbDeviceCdcVcomConfig,
         },
         {
             USB_DeviceMscCallback,
             (class_handle_t)NULL,
             &g_mscDiskClass,
         }
     };
     
     

   • Add a function for the USB device ISR.

     For EHCI,

     #if defined(USB_DEVICE_CONFIG_EHCI) && (USB_DEVICE_CONFIG_EHCI > 0U)
     void USBHS_IRQHandler(void)
     {
         USB_DeviceEhciIsrFunction(g_composite.deviceHandle);
     }
     #endif
     
     

     For KHC1,

     #if defined(USB_DEVICE_CONFIG_KHCI) && (USB_DEVICE_CONFIG_KHCI > 0U)
     void USB0_IRQHandler(void)
     {
         USB_DeviceKhciIsrFunction(g_composite.deviceHandle);
     }
     #endif
     
     

     For LPC IP3511,

     #if defined(USB_DEVICE_CONFIG_LPC3511IP) && (USB_DEVICE_CONFIG_LPC3511IP > 0U)
     void USB0_IRQHandler(void)
     {
         USB_DeviceLpc3511IpIsrFunction (g_composite.deviceHandle);
     }
     #endif
     
     

2. Enable the USB device clock.

   For EHC1,

   CLOCK_EnableUsbhs0Clock(kCLOCK_UsbSrcPll0, CLOCK_GetFreq(kCLOCK_PllFllSelClk));
   USB_EhciPhyInit(CONTROLLER_ID, BOARD_XTAL0_CLK_HZ);
   
   

   For KHC1,

   #if ((defined FSL_FEATURE_USB_KHCI_IRC48M_MODULE_CLOCK_ENABLED) && (FSL_FEATURE_USB_KHCI_IRC48M_MODULE_CLOCK_ENABLED))
   CLOCK_EnableUsbfs0Clock(kCLOCK_UsbSrcIrc48M, 48000000U);
   #else
   CLOCK_EnableUsbfs0Clock(kCLOCK_UsbSrcPll0, CLOCK_GetFreq(kCLOCK_PllFllSelClk));
   #endif /* FSL_FEATURE_USB_KHCI_IRC48M_MODULE_CLOCK_ENABLED */
   
   

   For LPC IP3511,

   CLOCK_EnableUsbfs0Clock(kCLOCK_UsbSrcFro, CLOCK_GetFreq(kCLOCK_FroHf));
   

3. Call the USB_DeviceClassInit function.

   if (kStatus_USB_Success != USB_DeviceClassInit(CONTROLLER_ID, &g_compositeDeviceConfigList, &g_composite.deviceHandle))
   {
       usb_echo("USB device composite demo init failed\r\n");
       return;
   }
   else
   {
       usb_echo("USB device composite demo\r\n");
       ……
   }
   
   

4. Get a handle for each class. For example,

   CDC virtual com:

   g_composite.cdcVcom.cdcAcmHandle = g_compositeDeviceConfigList.config[0].classHandle;
   

   MSC ramdisk:

   g_composite.mscDisk.mscHandle = g_compositeDeviceConfigList.config[1].classHandle;
   

5. Initialize each class application.

   Such as,

   CDC virtual com:

   USB_DeviceCdcVcomInit(&g_composite);
   

   MSC ramdisk:

   USB_DeviceMscDiskInit(&g_composite);
   

6. Set the interrupt priority and enable the USB device interrupt

   NVIC_SetPriority((IRQn_Type)irqNo, USB_DEVICE_INTERRUPT_PRIORITY);
   NVIC_EnableIRQ((IRQn_Type)irqNo);
   
   

7. Enable the USB device funtionally:

   USB_DeviceRun(g_composite.deviceHandle);
   

Parent topic:Application template