Part Number: MSP430AFE253
My requirements: collecting AC 50Hz signals, wave 64 points per week, sampling rate of Fs=50*32=1600; MCLK=SCLK=12MHz
Timer clock frequency =MCLK; sampling timer timing length =12000000/1600=7500;
In the timer interrupt program, start the ADC conversion, and reverse the P1.3 pin status to monitor the timer length, to get the frequency output =800Hz, indicating that the timer is set correctly
void TIMER_A_INIT(void)
{
u16 t;
//CCR0 = 7500;
t=12000000/（50*32）;
CCR0 = t;
TACTL = TASSEL_2 + TACLR+ MC_1;
CCTL0 = CCIE;
}
#pragma vector=TIMERA0_VECTOR
__interrupt void Timer_A (void)
{
SD24CCTL0 |= SD24SC;
P1OUT ^= BIT3; ;
}
void sd24_a_init(void)
{
u16 i;
SD24CTL = SD24SSEL_1+SD24DIV_2+SD24XDIV_1+SD24REFON; // 1.2V ref, SMCLK Fadc=12000000/(4*3)=1000000
SD24INCTL0 = SD24INCH_0+SD24GAIN_4+SD24INTDLY_3; // Interrupt on 1rd sample
SD24CCTL0 = SD24SNGL+SD24DF+SD24OSR_256+SD24IE; //单次转换模式,双极性模式补码输出,过采样256,,中断使能
for (i = 0; i < 0x4000; i++); // Delay for 1.2V ref startup
index=0;
}
#pragma vector=SD24_VECTOR
__interrupt void SD24AISR(void)
{
u8 i;
if(SD24IV==SD24IV_SD24MEM0)
{
ad_buf[index] = SD24MEM0;
if (++index == samplebuftime)
{
for(i=0;i<samplebuftime;i++) ad[i]=ad_buf[i];
index=0;
}
P1OUT ^= BIT4;
}
}
As set above, get the P1.4 pin output frequency =800 is correct. The sampling rate was 1600
But I read the AD sampling is wrong
Help me analyze where the problem is, thank you very much
