2.2.4.24 USB_DEVICE_EndpointEnable Function

C

USB_DEVICE_RESULT USB_DEVICE_EndpointEnable(
    USB_DEVICE_HANDLE usbDeviceHandle, 
    uint8_t interface, 
    USB_ENDPOINT_ADDRESS endpoint, 
    USB_TRANSFER_TYPE transferType, 
    size_t size
);

Summary

This function enables a device endpoint for the specified transfer type and size. A Vendor specific device application may typically call this function in response to a Set Interface request from the host. Note that Device Layer will enable endpoints contained in Alternate Setting 0 of an interface, when the host configures the device. If there is only one alternate setting in an interface, the application may not need to call the USB_DEVICE_EndpointEnable function.

If the device supports multiple alternate settings in an Interface, the device application must then disable an endpoint (if it was enabled) before re-enabling it with the new settings. The application can use the USB_DEVICE_EndpointIsEnabled function to check the status of the endpoint and USB_DEVICE_EndpointDisable function to disable the endpoint.

Precondition

The device should have been configured.

Parameters

Returns

USB_DEVICE_RESULT_OK - The endpoint was enabled successfully.

USB_DEVICE_RESULT_ERROR_ENDPOINT_INVALID - The specified instance was not provisioned in the application and is invalid.

Example

// The following code example checks if an Set Alternate request has
// been received and changes the endpoint characteristics based on the
// alternate setting. Endpoint is 1 and direction is device to host.
// Assume that endpoint size was 32 bytes in alternate setting 0.

if(setAlternateRequest)
{
    if(alternateSetting == 1)
    {
        // Check if the endpoint is already enabled.
        if(USB_DEVICE_EndpointIsEnabled(usbDeviceHandle, (0x1|USB_EP_DIRECTION_IN)))
        {
            // Disable the endpoint.
            USB_DEVICE_EndpointDisable(usbDeviceHandle, (0x1|USB_EP_DIRECTION_IN));
        }

        // Re-enable the endpoint with new settings
        USB_DEVICE_EndpointEnable(usbDeviceHandle, 0, (0x1|USB_EP_DIRECTION_IN)
                    USB_TRANSFER_TYPE_BULK, 64);
    }
}

Remarks

None.