然后呢？你是怎么应对这个的呢

不符合变量命名规则也没有宏定义，无端地就出现了个XXu这么个东西……请问下它是什么意思呢？

在msp430g2553.h看到的。

#define ADC10SSEL_0 (0*8u) /* ADC10OSC */
#define ADC10SSEL_1 (1*8u) /* ACLK */
#define ADC10SSEL_2 (2*8u) /* MCLK */
#define ADC10SSEL_3 (3*8u) /* SMCLK */

#define ADC10DIV_0 (0*0x20u) /* ADC10 Clock Divider Select 0 */
#define ADC10DIV_1 (1*0x20u) /* ADC10 Clock Divider Select 1 */
#define ADC10DIV_2 (2*0x20u) /* ADC10 Clock Divider Select 2 */
#define ADC10DIV_3 (3*0x20u) /* ADC10 Clock Divider Select 3 */
#define ADC10DIV_4 (4*0x20u) /* ADC10 Clock Divider Select 4 */
#define ADC10DIV_5 (5*0x20u) /* ADC10 Clock Divider Select 5 */
#define ADC10DIV_6 (6*0x20u) /* ADC10 Clock Divider Select 6 */
#define ADC10DIV_7 (7*0x20u) /* ADC10 Clock Divider Select 7 */

#define SHS_0 (0*0x400u) /* ADC10SC */
#define SHS_1 (1*0x400u) /* TA3 OUT1 */
#define SHS_2 (2*0x400u) /* TA3 OUT0 */
#define SHS_3 (3*0x400u) /* TA3 OUT2 */

#define INCH_0 (0*0x1000u) /* Selects Channel 0 */
#define INCH_1 (1*0x1000u) /* Selects Channel 1 */
#define INCH_2 (2*0x1000u) /* Selects Channel 2 */
#define INCH_3 (3*0x1000u) /* Selects Channel 3 */
#define INCH_4 (4*0x1000u) /* Selects Channel 4 */
#define INCH_5 (5*0x1000u) /* Selects Channel 5 */
#define INCH_6 (6*0x1000u) /* Selects Channel 6 */
#define INCH_7 (7*0x1000u) /* Selects Channel 7 */
#define INCH_8 (8*0x1000u) /* Selects Channel 8 */
#define INCH_9 (9*0x1000u) /* Selects Channel 9 */
#define INCH_10 (10*0x1000u) /* Selects Channel 10 */
#define INCH_11 (11*0x1000u) /* Selects Channel 11 */
#define INCH_12 (12*0x1000u) /* Selects Channel 12 */
#define INCH_13 (13*0x1000u) /* Selects Channel 13 */
#define INCH_14 (14*0x1000u) /* Selects Channel 14 */
#define INCH_15 (15*0x1000u) /* Selects Channel 15 */

据我猜测 u 是 unsigned 的意思

u 应该没有关系吧！