MSPF测周法测量信号频率
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M S P430F5529测量频率
-----测周法信号变换电路
过零比较器，lm393输出上拉电阻，两电阻分压
程序
#include <>
#include ""
#include ""
//测周法，在捕获过程中，定时溢出不能被检测出，选择时钟频率为低频时能测出低频，频率高能测出频率高的部分
/*
*
*/
long long start=0;
//long long int stop=0;
double fre=;
unsigned char i=0;
unsigned char over=0;
void SetVcoreUp (unsigned int level)
{
// Open PMM registers for write
PMMCTL0_H = PMMPW_H;
// Set SVS/SVM high side new level
SVSMHCTL = SVSHE + SVSHRVL0 * level + SVMHE + SVSMHRRL0 * level;
// Set SVM low side to new level
SVSMLCTL = SVSLE + SVMLE + SVSMLRRL0 * level;
// Wait till SVM is settled
while ((PMMIFG & SVSMLDLYIFG) == 0);
// Clear already set flags
PMMIFG &= ~(SVMLVLRIFG + SVMLIFG);
// Set VCore to new level
PMMCTL0_L = PMMCOREV0 * level;
// Wait till new level reached
if ((PMMIFG & SVMLIFG))
while ((PMMIFG & SVMLVLRIFG) == 0);
// Set SVS/SVM low side to new level
SVSMLCTL = SVSLE + SVSLRVL0 * level + SVMLE + SVSMLRRL0 * level;
// Lock PMM registers for write access
PMMCTL0_H = 0x00;
}
void init_clock()
{
SetVcoreUp (0x01);
SetVcoreUp (0x02);
SetVcoreUp (0x03);
UCSCTL3 = SELREF_2; // Set DCO FLL reference = REFO UCSCTL4 |= SELA_2; // Set ACLK = REFO
__bis_SR_register(SCG0); // Disable the FLL control loop UCSCTL0 = 0x0000; // Set lowest possible DCOx, MODx UCSCTL1 = DCORSEL_7; // Select DCO range 50MHz operation UCSCTL2 = FLLD_0 + 609; // Set DCO Multiplier for 25MHz // (N + 1) * FLLRef = Fdco
// (762 + 1) * 32768 = 25MHz // Set FLL Div = fDCOCLK/2
__bic_SR_register(SCG0); // Enable the FLL control loop __delay_cycles(782000);
do
{
UCSCTL7 &= ~(XT2OFFG + XT1LFOFFG + DCOFFG);
// Clear XT2,XT1,DCO fault flags SFRIFG1 &= ~OFIFG; // Clear fault flags
}while (SFRIFG1&OFIFG); // Test oscillator fault flag
}
void send_char(char sc)
{
UCA0TXBUF=sc;
while(!(UCA0IFG&UCTXIFG));
}
void send_string(char *s)
{
while(*s!='\0')
{
send_char(*s++);
}
}
init_uart()
{
P3SEL |= BIT3+BIT4; // ,4 = USCI_A0 TXD/RXD
UCA0CTL1 |= UCSWRST; // **Put state machine in reset** UCA0CTL1 |= UCSSEL__SMCLK; // SMCLK
UCA0BR0 = 173; // 1MHz 115200 (see User's Guide) UCA0BR1 = 0; // 1MHz 115200
UCA0MCTL |= UCBRS_5 + UCBRF_0; // Modulation UCBRSx=1, UCBRFx=0 UCA0CTL1 &= ~UCSWRST; // **Initialize USCI state machine** UCA0IE |= UCRXIE; // Enable USCI_A0 RX interrupt