Macros
USBXpress

Description

Macros.

Macros

#define USBX_STRING_DESC (_name, ...)
Macro for creating USB-Compliant UTF-16LE UNICODE string descriptor.
#define USBX_BUF (x, y)   SL_ALIGN(4) uint8_t x[((y) + 3) & ~3] SL_ATTRIBUTE_ALIGN(4)
Macro for creating WORD (4 byte) aligned uint8_t array with size which is a multiple of WORD size.
#define STATIC_USBX_BUF (x, y)
Macro for creating WORD (4 byte) aligned static uint8_t array with size which is a multiple of WORD size.

Macro Definition Documentation

◆ USBX_STRING_DESC

#define USBX_STRING_DESC ( _name,
...
)
Value:
SL_PACK_START(1) \
typedef struct \
{ \
uint8_t len; \
uint8_t type; \
char16_t name[1 + sizeof (( char16_t []){ __VA_ARGS__ }) / 2]; \
} SL_ATTRIBUTE_PACKED _##_name; \
SL_PACK_END() \
SL_ALIGN(4) \
SL_PACK_START(1) \
static const _##_name _name SL_ATTRIBUTE_ALIGN(4) = \
{ \
.len = sizeof (_##_name) - 2, \
.type = 3, \
.name = { __VA_ARGS__ }, \
.name[(( sizeof (_##_name) - 2) / 2) - 1] = '\0' \
} \
SL_PACK_END()

Macro for creating USB-Compliant UTF-16LE UNICODE string descriptor.


Example: USBX_STRING_DESC(iManufacturer, 'S','i','l','i','c','o','n',' ' \ 'L','a','b','s');

Note
The size of the resulting struct will be two bytes larger than a USB string descriptor. This is to accommodate a terminating null char for the string. The value assigned to the 'len' member does not take this into account and is therefore correct USB-wise.

◆ USBX_BUF

#define USBX_BUF ( x,
y
) SL_ALIGN(4) uint8_t x[((y) + 3) & ~3] SL_ATTRIBUTE_ALIGN(4)

Macro for creating WORD (4 byte) aligned uint8_t array with size which is a multiple of WORD size.


Example:
USBX_BUF(rxBuffer, 37) ; => uint8_t rxBuffer[40];

Note
Any data buffer which is written to or read by the USB hardware must be aligned on a WORD (4 byte) boundary. This macro provides an easy way to create USB data buffers which are guaranteed to be correctly aligned.

◆ STATIC_USBX_BUF

#define STATIC_USBX_BUF ( x,
y
)
Value:
SL_ALIGN(4) \
static uint8_t x[((y) + 3) & ~3] SL_ATTRIBUTE_ALIGN(4)

Macro for creating WORD (4 byte) aligned static uint8_t array with size which is a multiple of WORD size.


Example:
STATIC_USBX_BUF(rxBuffer, 37) ; => uint8_t rxBuffer[40];

Note
Any data buffer which is written to or read by the USB hardware must be aligned on a WORD (4 byte) boundary. This macro provides an easy way to create static USB data buffers which are guaranteed to be correctly aligned.