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//******************************************************************************
// MSP430F22x4 Demo - Timer_A, PWM TA1-2, Up Mode, HF XTAL ACLK
//
// Description: This program generates two PWM outputs on P1.2,3 using
// Timer_A configured for up mode. The value in TACCR0, 512-1, defines the
// period and the values in TACCR1 and TACCR2 the PWM duty cycles. Using
// HF XTAL ACLK as TACLK, the timer period is HF XTAL/512 with a 75% duty
// cycle on P1.2 and 25% on P1.3.
// ACLK = MCLK = TACLK = HF XTAL
// //* HF XTAL REQUIRED AND NOT INSTALLED ON FET *//
// //* Min Vcc required varies with MCLK frequency - refer to datasheet *//
//
// MSP430F22x4
// -----------------
// /|\| XIN|-
// | | | HF XTAL (3 16MHz crystal or resonator)
// --|RST XOUT|-
// | |
// | P1.2/TA1|--> TACCR1 - 75% PWM
// | P1.3/TA2|--> TACCR2 - 25% PWM
//
// A. Dannenberg
// Texas Instruments Inc.
// April 2006
// Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.41A
//******************************************************************************
#include "msp430x22x4.h"
void main(void)
{
volatile unsigned int i;
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
BCSCTL1 |= XTS; // ACLK = LFXT1 = HF XTAL
BCSCTL3 |= LFXT1S1; // LFXT1S1 = 3-16Mhz
do
{
IFG1 &= ~OFIFG; // Clear OSCFault flag
for (i = 0xFF; i > 0; i--); // Time for flag to set
}
while (IFG1 & OFIFG); // OSCFault flag still set?
BCSCTL2 |= SELM_3; // MCLK= LFXT1 (safe)
P1DIR |= 0x0C; // P1.2 and P1.3 output
P1SEL |= 0x0C; // P1.2 and P1.3 TA1/2 otions
TACCR0 = 512 - 1; // PWM Period
TACCTL1 = OUTMOD_7; // TACCR1 reset/set
TACCR1 = 384; // TACCR1 PWM duty cycle
TACCTL2 = OUTMOD_7; // TACCR2 reset/set
TACCR2 = 128; // TACCR2 PWM duty cycle
TACTL = TASSEL_1 + MC_1; // ACLK, up mode
__bis_SR_register(LPM0_bits); // Enter LPM0
}
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