typedef struct {
  __IO uint8_t A;
  __IO uint8_t B;
  uint16_t RES;
} DEV_t;

  DEV_t Dev;
  DEV_t *pDev = &Dev;

  pDev->A = 0x55;
  pDev->B = 0xAA;
  (uint16_t)pDev->A = 0x3333;
  (uint32_t)pDev->A = 0x01234567;

typedef struct
{
  __IO uint32_t DR;         /*!< CRC Data register,             Address offset: 0x00 */
  __IO uint8_t  IDR;        /*!< CRC Independent data register, Address offset: 0x04 */
  uint8_t       RESERVED0;  /*!< Reserved, 0x05                                      */
  uint16_t      RESERVED1;  /*!< Reserved, 0x06                                      */
  __IO uint32_t CR;         /*!< CRC Control register,          Address offset: 0x08 */
} CRC_TypeDef;