现附上示例程序:
//******************************************************************************
// MSP430G2x33/G2x53 Demo - ADC10, Sample A1, 1.5V, TA1 Trig, Set P1.0 if < 0.5V
//
// Description: A1 is sampled 16/second (ACLK/2048) with reference to 1.5V.
// Timer_A is run in upmode and TA1 is used to automatically trigger
// ADC10 conversion, TA0 defines the period. Internal oscillator times sample
// (16x) and conversion (13x). Inside ADC10_ISR if A1 < 0.5Vcc, P1.0 is set,
// else reset. Normal mode is LPM3.
// //* An external watch crystal on XIN XOUT is required for ACLK *//
// D. Dang
// Texas Instruments Inc.
// December 2010
// Built with CCS Version 4.2.0 and IAR Embedded Workbench Version: 5.10
//******************************************************************************
#include "msp430g2553.h"
void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
ADC10CTL1 = SHS_1 + CONSEQ_2 + INCH_1; // TA1 trigger sample start
ADC10CTL0 = SREF_1 + ADC10SHT_2 + REFON + ADC10ON + ADC10IE;
__enable_interrupt(); // Enable interrupts.
TACCR0 = 30; // Delay to allow Ref to settle
TACCTL0 |= CCIE; // Compare-mode interrupt.
TACTL = TASSEL_2 + MC_1; // TACLK = SMCLK, Up mode.
LPM0; // Wait for delay.
TACCTL0 &= ~CCIE; // Disable timer Interrupt
__disable_interrupt();
ADC10CTL0 |= ENC; // ADC10 Enable
ADC10AE0 |= 0x02; // P1.1 ADC10 option select
P1DIR |= 0x01; // Set P1.0 output
TACCR0 = 2048-1; // PWM Period
TACCTL1 = OUTMOD_3; // TACCR1 set/reset
TACCR1 = 2047; // TACCR1 PWM Duty Cycle
TACTL = TASSEL_1 + MC_1; // ACLK, up mode
__bis_SR_register(LPM3_bits + GIE); // Enter LPM3 w/ interrupts
}
// ADC10 interrupt service routine
#pragma vector=ADC10_VECTOR
__interrupt void ADC10_ISR(void)
{
if (ADC10MEM < 0x155) // ADC10MEM = A1 < 0.5V?
P1OUT &= ~0x01; // Clear P1.0 LED off
else
P1OUT |= 0x01; // Set P1.0 LED on
}
#pragma vector=TIMER0_A0_VECTOR
__interrupt void ta0_isr(void)
{
TACTL = 0;
LPM0_EXIT; // Exit LPM0 on return
}
以下是7点问题：
1.__enable_interrupt();进入的是ADC10_VECTOR中断还是TIMER0_A0_VECTOR中断？
2.这段代码中TIMER0_A0_VECTOR中断起到的又是什么作用？
3.这段代码中并没有设置ADC10SSELx,是没有设置，还是设置成了0：ADC10OSC?
4.他选择了CONSEQ = 2，那MSC位就默认为0了是吗？
5.整段程序竟然没有ADC10SC？难道不用Start sample-and-conversion了吗？
6.以下两个Timer的设置:
TACCR0 = 30; // Delay to allow Ref to settle
TACCTL0 |= CCIE; // Compare-mode interrupt.
TACTL = TASSEL_2 + MC_1; // TACLK = SMCLK, Up mode.
LPM0; // Wait for delay.
TACCTL0 &= ~CCIE; // Disable timer Interrupt
这里设置的Timer只是为了产生一个delay的？
TACCR0 = 2048-1; // PWM Period
TACCTL1 = OUTMOD_3; // TACCR1 set/reset
TACCR1 = 2047; // TACCR1 PWM Duty Cycle
TACTL = TASSEL_1 + MC_1; // ACLK, up mode
而这里的Timer才是为了触发ADC转换的？
7.
ADC10AE0 |= 0x02; // P1.1 ADC10 option select
这句的意思是说，选择P1.1作为信号的输入端吗？（之前他设置了INCH = 1）
P1DIR |= 0x01; // Set P1.0 output
这个把P1.0设置成输出端是为什么？
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问题很多，而且颇琐碎，谢谢各位了!
