MSP430F5529测频法测量信号频率.pdf

MSP430F5529 测量频率 测频法 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 msp430f5529.h #include stdio.h //测频法，上限 1Mhz //看门狗定时 1s，开门狗中断处理程序开启捕获器，捕获 1s 中所有的上升脉冲，脉冲个数即为频 率 /* 优化的反向可以将开门够定时 1S 使用定时器去定时 1s * main.c */ long fre=0; char buf[60]=\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 SVSMLDL YIFG) == 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