msp430x24x_compa_02.c

德州仪器公司提供的msp430x24x和msp430x23x系列单片机的示例程序. 内含单片机各模块的具体程序.

//******************************************************************************
//   MSP430x24x Demo - Comparator A, Poll input CA0, CA exchange, result in P1.0
//
//   Description: The Voltage at pin CA0 (Vcompare) is compared with reference
//   voltage of 0.5*Vcc. LED is toggled when Vcompare crosses the ref voltage.
//
//                 MSP430F249
//             -----------------
//         /|\|                 |
//          | |                 |
//          --|RST      P2.3/CA0|<--Vcompare
//            |                 |
//            |             P1.0|-->CAOUT - LED
//
//  B. Nisarga
//  Texas Instruments Inc.
//  September 2007
//  Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.42A
//******************************************************************************
#include  <msp430x24x.h>

void main(void)
{
  WDTCTL = WDTPW+WDTHOLD;                   // Stop WDT

  CACTL1 = CAEX+CAON+CAREF_2+CARSEL;        // Enable comp, ref = 0.5*Vcc = Vin+
  CACTL2 = P2CA0;                           // Pin to CA0 -> V-

  P1DIR |= 0x001;                           // P1.0 = o/p direction (CAOUT- LED)
  P1SEL |= 0x001;                           // P1.0 - CAOUT, option select
}