请教个问题,关于AD采样速度的,资料上说MSP430F149 AD采样速度高达200kbit/s,这个采样速度是指什么啊?是采样+转换的速度吗?我现在用8MHz作为ADC12CLK,系统主时钟也是8M,怎么设置出最高的采样速度?能提供AD设置代码最好了,非常感谢!!!
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2. 采样转换时间,又叫采样周期,它表示采样的时间间隔。
3. CPU的时钟频率分频后供给各个外设使用,其中ADC10CTL1寄存器中的ADC10DIVx就会用来设置ADC的时钟分频的。
4. 这里提供一个官方例程给你参考:
//******************************************************************************
// MSP430G2x32/G2x52 Demo - ADC10, Sample A1, AVcc Ref, Set P1.0 if > 0.5*AVcc
//
// Description: A single sample is made on A1 with reference to AVcc.
// Software sets ADC10SC to start sample and conversion - ADC10SC
// automatically cleared at EOC. ADC10 internal oscillator times sample (16x)
// and conversion. In Mainloop MSP430 waits in LPM0 to save power until ADC10
// conversion complete, ADC10_ISR will force exit from LPM0 in Mainloop on
// reti. If A1 > 0.5*AVcc, P1.0 set, else reset.
//
// MSP430G2x32/G2x52
// -----------------
// /|| XIN|-
// | | |
// --|RST XOUT|-
// | |
// >---|P1.1/A1 P1.0|-->LED
//
// D. Dang
// Texas Instruments Inc.
// December 2010
// Built with CCS Version 4.2.0 and IAR Embedded Workbench Version: 5.10
//******************************************************************************
#include "msp430g2452.h"
void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
ADC10CTL0 = ADC10SHT_2 + ADC10ON + ADC10IE; // ADC10ON, interrupt enabled
ADC10CTL1 = INCH_1; // input A1
ADC10AE0 |= 0x02; // PA.1 ADC option select
P1DIR |= 0x01; // Set P1.0 to output direction
for (;;)
{
ADC10CTL0 |= ENC + ADC10SC; // Sampling and conversion start
__bis_SR_register(CPUOFF + GIE); // LPM0, ADC10_ISR will force exit
if (ADC10MEM < 0x1FF)
P1OUT &= ~0x01; // Clear P1.0 LED off
else
P1OUT |= 0x01; // Set P1.0 LED on
}
}
// ADC10 interrupt service routine
#pragma vector=ADC10_VECTOR
__interrupt void ADC10_ISR(void)
{
__bic_SR_register_on_exit(CPUOFF); // Clear CPUOFF bit from 0(SR)
}
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