lpm4

yqsqqq

 #include  "msp430g2553.h"

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  BCSCTL1 = CALBC1_1MHZ;                    // Set DCO
  DCOCTL = CALDCO_1MHZ;
  1DIR = 0xFF;                             // All 1.x outputs
  1OUT = 0;                                // All 1.x reset
  1SEL = BIT1 + BIT2 + BIT4;                     // 1.1 = RXD, 1.2=TXD
  1SEL2 = BIT1 + BIT2;                     // 1.4 = SMCLK, others GPIO
  2DIR = 0xFF;                             // All P2.x outputs
  P2OUT = 0;                                // All P2.x reset  
  P3DIR = 0xFF;                             // All P3.x outputs
  P3OUT = 0;                                // All P3.x reset  
  UCA0CTL1 |= UCSSEL_2;                     // SMCLK
  UCA0BR0 = 8;                              // 1MHz 115200
  UCA0BR1 = 0;                              // 1MHz 115200
  UCA0MCTL = UCBRS2 + UCBRS0;               // Modulation UCBRSx = 5
  UCA0CTL1 &= ~UCSWRST;                     // **Initialize USCI state machine**
  IE2 |= UCA0RXIE;                          // Enable USCI_A0 RX interrupt

  __bis_SR_register(LPM4_bits + GIE);       // Enter LPM4, interrupts enabled
}

// Echo back RXed character, confirm TX buffer is ready first
#pragma vector=USCIAB0RX_VECTOR
__interrupt void USCI0RX_ISR(void)
{
  while (!(IFG2&UCA0TXIFG));                // USCI_A0 TX buffer ready?
  UCA0TXBUF = UCA0RXBUF;                    // TX -> RXed character
}
求解释  LPM4能唤醒？ 

正点原子

不懂,帮顶.