// Using an external potentiometer, an unknown voltage is applied to P1.1.. // Comparator_A compares the unknown voltage to an internal reference // voltage, in this example 0.25*VCC.. D
Trang 1//****************************************************************************** // MSP430G2x12/G2x52 Demo - Comp_A, Detect Threshold, Set P1.0 if P1.1 > 0.25*Vcc
//
// Description: Use Comparator_A to detect a voltage threshold
// Using an external potentiometer, an unknown voltage is applied to P1.1 // Comparator_A compares the unknown voltage to an internal reference
// voltage, in this example 0.25*VCC If the unknown voltage is higher
// than 0.25*VCC, P1.0 is set, if not, P1.0 is reset
// ACLK = n/a, MCLK = SMCLK = default DCO
//
// MSP430G2x12/G2x52
//
-// /|\ |
XIN|-// | | |
// -|RST
XOUT|-// | | |
// R<-|P1.1/CA1 P1.0| >LED
// | | |
// -|VSS
//
// 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
P1DIR |= 0x01; // P1.0 output
CACTL1 = CARSEL + CAREF0 + CAON; // 0.25 Vcc = -comp, on
CACTL2 = P2CA4; // P1.1/CA1 = +comp
while (1) // Test comparator_A output
{
if ((CAOUT & CACTL2))
P1OUT |= 0x01; // if CAOUT set, set P1.0
else P1OUT &= ~0x01; // else reset
}
}