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MSP430FR5994: MSP430FR5994高频时钟无法选择

Part Number:MSP430FR5994

使用了MSP430FR5994单片机,使用8MHz的晶体,连接至XT2OUT和XT2IN,作为高速时钟使用。通过配置PJSEL1.6=0,PJSEL0.6=1,并关闭HFXTOFF。在晶振错误标识为0,时,切换至HF,但是输出是4.MHz。通过CTL2可以正确设置MCLK和SMCLK为DCO、MODCLK、ACLk,但是就是无法使用HF。选择了HF后得到的依然是MODCLK时钟,也就是4.8MHz。不知何故?请指教!谢谢!

Susan Yang:

请问您是否有测试下面的例程?在此例程中使用的是8Mhz的晶振

// Description: Configure ACLK = LFXT, SMCLK = HFXT and MCLK = DCO// NOTE1: 32768Hz and 8MHz crystals required!

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//******************************************************************************
//MSP430FR5x9x Demo - ACLK = XT1 = 32768Hz, SMCLK= XT2 = 8MHz, MCLK = DCO
//
//Description: Configure ACLK = LFXT, SMCLK = HFXT and MCLK = DCO
//NOTE1: 32768Hz and 8MHz crystals required!
//
//MSP430FR5994
//---------------
///|\||
//| ||-LFXIN
//--|RST|-LFXOUT
//||
//||-HFXIN
//||-HFXOUT
//||
//|P1.0|---> LED
//|P2.0|---> ACLK = 32768Hz
//|P3.4|---> SMCLK = 8MHz
//
//William Goh
//Texas Instruments Inc.
//October 2015
//Built with IAR Embedded Workbench V6.30 & Code Composer Studio V6.1
//******************************************************************************
#include <msp430.h>int main(void)
{WDTCTL = WDTPW | WDTHOLD;// Configure GPIOP1OUT = 0;P1DIR = BIT0;// For LEDP2DIR |= BIT0;P2SEL0 |= BIT0;// Output ACLKP2SEL1 |= BIT0;P3DIR |= BIT4;P3SEL1 |= BIT4;// Output SMCLKP3SEL0 |= BIT4;PJSEL0 |= BIT4 | BIT5 | BIT6 | BIT7;// For XT1 and XT2// Disable the GPIO power-on default high-impedance mode to activate// previously configured port settingsPM5CTL0 &= ~LOCKLPM5;CSCTL0_H = CSKEY_H;// Unlock CS registersCSCTL1 = DCOFSEL_6;// Set DCO to 8MHzCSCTL2 = SELA__LFXTCLK | SELS__HFXTCLK | SELM__DCOCLK;CSCTL3 = DIVA__1 | DIVS__1 | DIVM__1;// Set all dividers to 1CSCTL4 |= LFXTDRIVE_3 | HFXTDRIVE_3;CSCTL4 &= ~(LFXTOFF | HFXTOFF);do{CSCTL5 &= ~(LFXTOFFG | HFXTOFFG);// Clear XT1 and XT2 fault flagSFRIFG1 &= ~OFIFG;} while (SFRIFG1 & OFIFG);// Test oscillator fault flagCSCTL0_H = 0;// Lock CS registerswhile (1){P1OUT ^= 0x01;// Toggle LED__delay_cycles(8000000);// Wait 8,000,000 CPU Cycles}
}

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