msp430F 5438时钟配置为25M时

MSP430F5438外接25M晶振。

void initClock(void)

{

// 初始化P7.0(#13)和P7.1(#14)为复用功能, XT1 外部时钟晶体接线

GPIO_setAsPeripheralModuleFunctionInputPin( GPIO_PORT_P7 , GPIO_PIN0 | GPIO_PIN1 );

// 启动XT1

//Initializes the XT1 crystal oscillator with no timeout

//In case of failure, code hangs here.

//For time-out instead of code hang use UCS_LFXT1StartWithTimeout()

UCS_LFXT1Start( UCS_XT1_DRIVE0 , UCS_XCAP_3);

// DCO参考时钟选择XT1，选择了默认参数

//UCS_clockSignalInit( UCS_FLLREF, UCS_XT1CLK_SELECT , UCS_CLOCK_DIVIDER_1 );

// 初始化P5.2(#89)和P5.3(#90)为复用功能, XT2 外部时钟晶体接线

GPIO_setAsPeripheralModuleFunctionInputPin( GPIO_PORT_P5 , GPIO_PIN2 | GPIO_PIN3 );

// 启动XT2

UCS_XT2Start( UCS_XT2DRIVE_24MHZ_32MHZ );

// DCO参考时钟选择XT1，选择了默认参数

//UCS_clockSignalInit( UCS_FLLREF, UCS_XT1CLK_SELECT , UCS_CLOCK_DIVIDER_1 );

// ACLK参考时钟源选择REFO, 32768Hz

//UCS_clockSignalInit(UCS_ACLK,

UCS_REFOCLK_SELECT,UCS_CLOCK_DIVIDER_1);

// DCO参考时钟源选择REFO，32768Hz

//UCS_clockSignalInit(UCS_FLLREF, UCS_REFOCLK_SELECT , UCS_CLOCK_DIVIDER_1);

// DCO时钟16MHz, used as MCLK and SMCLK frequency

// 该函数第1个参数为系统工作频率16384KHz/1024=16MHz，第2个参数为工作频率/DCO参考频率=16*1024*1024/32768=512

#define FRQ_DIV 1

//UCS_initFLLSettle(16384/FRQ_DIV , 512/FRQ_DIV);

//! Initializes the XT2 crystal oscillator, which supports crystal frequencies

//! between 4 MHz and 32 MHz, depending on the selected drive strength. Loops

//! until all oscillator fault flags are cleared, with no timeout. See the

//! device-specific data sheet for appropriate drive settings.

UCS_clockSignalInit(UCS_MCLK,UCS_XT2CLK_SELECT ,UCS_CLOCK_DIVID ER_1);

//SMCLK参考时钟源选择DCO,16MHz/4=4MHz,4*1024*1024=4194304Hz

//UCS_clockSignalInit(UCS_SMCLK,UCS_DCOCLK_SELECT,UCS_CLOCK_DIV IDER_4);

UCS_clockSignalInit(UCS_SMCLK,UCS_XT2CLK_SELECT,UCS_CLOCK_DIVI DER_4);

//延时0.5秒, 让时钟源稳定

delay_ms(500);

UCS_setExternalClockSource(32768,MCLK_FRQ);

cvMCLK = UCS_getMCLK();

cvSMCLK = UCS_getSMCLK();

cvACLK = UCS_getACLK();

}