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//*****************************************************************************
// MSP430F54x Demo - FLL+, Output 32kHz Xtal + HF Xtal + Internal DCO
//
// Description: This program demonstrates using an external 32kHz crystal to
// supply ACLK, and using a high speed crystal or resonator to supply SMCLK.
// MLCK for the CPU is supplied by the internal DCO. The 32kHz crystal
// connects between pins Xin and Xout. The high frequency crystal or
// resonator connects between pins XT2IN and XT2OUT. The DCO clock is
// generated internally and calibrated from the 32kHz crystal. ACLK is
// brought out on pin P11.0, SMCLK is brought out on P11.2, and MCLK is
// brought out on pin P11.1.
// ACLK = LFXT1 = 32768Hz, MCLK = default DCO = 32 x ACLK = 1048576Hz
// SMCLK = HF XTAL
// //* An external watch crystal between XIN & XOUT is required for ACLK *//
//
// NOTE: External matching capacitors must be added for the high
// speed crystal or resonator as required.
//
// MSP430F5438
// -----------------
// /|\ | XIN|-
// | | | 32kHz
// ---|RST XOUT|-
// | |
// | |
// | XT2IN|-
// | | HF XTAL or Resonator (add capacitors)
// | XT2OUT|-
// | |
// | P11.0|--> ACLK = 32kHz Crystal Out
// | |
// | P11.2|--> SMCLK = High Freq Xtal or Resonator Out
// | |
// | P11.1|--> MCLK = Default DCO Frequency
// | |
// | |
//
// W. Goh
// Texas Instruments Inc.
// February 2009
// Built with CCE Version: 3.2.2 and IAR Embedded Workbench Version: 4.11B
//******************************************************************************
#include "msp430x54x.h"
void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
P11DIR = BIT2 + BIT1 + BIT0; // P11.2,1,0 to output direction
P11SEL = BIT2 + BIT1 + BIT0; // P11.2 to output SMCLK, P11.1
// to output MCLK and P11.0 to
// output ACLK
P5SEL |= 0x0C; // Port select XT2
P7SEL |= 0x03; // Port select XT1
UCSCTL6 &= ~(XT1OFF + XT2OFF); // Set XT1 & XT2 On
UCSCTL6 |= XCAP_3; // Internal load cap
// Loop until XT1,XT2 & DCO stabilizes
do
{
UCSCTL7 &= ~(XT2OFFG + XT1LFOFFG + XT1HFOFFG + DCOFFG);
// Clear XT2,XT1,DCO fault flags
SFRIFG1 &= ~OFIFG; // Clear fault flags
}while (SFRIFG1&OFIFG); // Test oscillator fault flag
UCSCTL6 &= ~XT2DRIVE0; // Decrease XT2 Drive according to
// expected frequency
UCSCTL4 |= SELA_0 + SELS_5; // Select SMCLK, ACLK source and DCO source
while(1); // Loop in place
}
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