In the Cypress example projects for the CX3 device, the USB string descriptors are defined like this:
/* Standard manufacturer string descriptor */
const uint8_t CyCx3USBManufactureDscr[] =
{
0x10, /* Descriptor size */
CY_U3P_USB_STRING_DESCR, /* Device descriptor type */
'C',0x00, /* Manufacturer String */
'y',0x00,
'p',0x00,
'r',0x00,
'e',0x00,
's',0x00,
's',0x00
};
I would like to suggest a tidier method, which is easier to read, and less prone to bugs. First we define a macro:
#define USB_STRING_DESC(S) ((char const*)&(struct{ char const p[2]; wchar_t const s[sizeof(S)]; }) { {(sizeof(S)), CY_U3P_USB_STRING_DESCR}, S})
Now we can define our descriptors using a single line each:
const uint8_t *CyCx3USBManufactureDscr = USB_STR_DESC(L"Cypress");
const uint8_t *CyCx3USBProductDscr = USB_STR_DESC(L"CX3 Camera");
const uint8_t *CyCx3USBConfigSSDscr = USB_STR_DESC(L"USB-3.0");
const uint8_t *CyCx3USBConfigHSDscr = USB_STR_DESC(L"USB-2.1");
const uint8_t *CyCx3USBConfigFSDscr = USB_STR_DESC(L"USB-1.1");
