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SREF_1 ....makes VR+=Vref+ and VR_= Avss..(in my case zero)
INCH_11.....is the voltage divider initiation I was talking about...(AVCC - AVss)/2
this what this statement does??

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the battery is connected to AVCC and Avss(ground)

http://www.ti.com/li...9f/slau049f.pdf
Chapter 17 of this user guide....page 17-3 for circuit diagram for internal ADC of the microcontroller
page 17-25 for ADC12MCTL definition

Yes . The hardware is the same one that I m using...

well...I have seen the example codes....But where exactly do u think a while statement is needed??


The LCD information can all be found here..in these two links

http://www.softbaugh...ecification.pdf
http://www.softbaugh...rPartNo=SBLCDA4

http://cnx.org/conte...test/LCD_defs.h
This is the header file I am using....in my code...Thats wher BAT_FULL and all variables comes from

Although I doubt that I have made any mistakes with LCD configuration. I made a whole alarm clock on this
I think the settings should be fine....

cheers

Forgot to tell I use the ADC12_07 example code as reference for this particular code...!

Well it doesnt fix the problem... It displays the full voltage symbol...however..it doesnt respond to the voltage change...i mean when voltage falls below 2.5 v...it should display low battery symbol.

I dont think i need the while loop...because ADC12CTL0 = REFON + REF2_5V + ADC12ON + SHT0_8+ MSC......the MSC command ensures that the next conversion should be done automatically after another...so in case of a new conversion..interrupt routine will be called...is it not??

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if (BAT_VOLT>=1.25){
BAT_FULL;
}else{
BAT_50;}
BAT_FULL and BAT_50....these are variables defined in LCD_defs.h for displaying symbols on LCD screen

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Yes.. just realised that...I will change it to double as it will take a fraction

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C compilers do not allow to get access to the CPU control registers. On MSP430 the CPU Register R2 is used as the Status Register (SR).
There are bits within the SR that allows to configure the chip into its Low Power Modes and there is the General Interrupt Enable (GIE) bit.
So if you want to change either the LPM mode or set/clear the GIE bit you use an intrinsic function of the C compiler - that's the __bis_SR_register() function.

This line just configures the system to a low power mode ...definitions are defined in datasheet.. It goes into Low power mode with the interrupt.
code with changes!!

#include  <msp430fg4618.h>
#include <stdint.h>
#include<intrinsics.h> //For add_bcd_short function to be used
#include  "LCD_defs.h" // P7_A1...P1_A0....all defined here
unsigned int ADCValue;
unsigned double BAT_VOLT;
void LCD_all_off(void);

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

  //LCD_A S0-S21 configuration
            LCDAPCTL0 = LCDS24 | LCDS20 | LCDS16 | LCDS12 | LCDS8 | LCDS4;

            // LCD_A configuration
            LCDACTL = LCDFREQ_192 | LCD4MUX | LCDSON | LCDON;   // (ACLK = 32768)/192, 4-mux LCD, LCD_A on, Segments on
            LCDAVCTL0 = LCDCPEN;                                // Charge pump enable
            LCDAVCTL1 = VLCD_3_44;
            LCD_all_off();

 // ADC CONFIGURATION

  P6SEL |= 0x01;                            // Enable A/D channel A0
  //ADC12CTL0 = ADC12ON + SHT0_8 + MSC;       // Turn on ADC12, set sampling time
  ADC12CTL0 = REFON + REF2_5V + ADC12ON + SHT0_8+ MSC;//reference used 2.5 v , MSC= multiple sample and conversion starts another
  	  	  	  	  	  	  	  	  	  	  	  	  	  //conversions as one ends// SHT0_8 ..256 cycles of clock
  ADC12CTL1 = SHP + CONSEQ_2;               // Use sampling timer, set mode//repeat single channel conversions
  ADC12IE = 0x01;                           // Enable ADC12IFG.0
  ADC12CTL0 |= ENC; 						 // Enable conversions
  ADC12MCTL0=SREF_1+INCH_11;                    // selecting reference and channel 11(( Avcc-Avss)/2)
  __enable_interrupt();                     // Enable interrupts
  ADC12CTL0 |= ADC12SC;                     // Start conversion
 for(;;)/>{   
 __bis_SR_register(LPM3_bits + GIE);
 }
}

#pragma vector = ADC12_VECTOR
__interrupt void ADC12_ISR(void)
{
ADCValue= ADC12MEM0;  // Move  conversion result, IFG is cleared
BAT_VOLT= (unsigned double)((ADCValue)*(2.5/4095)) ;   //coverting the value from ADC into voltage

if (BAT_VOLT>=1.25){        //using voltage divide 2.5/2 =1.25 (not sure abt this bit??)
	BAT_FULL;             // Any battery value above 2.5 gives symbol battery full
}else{
		BAT_50;}              //any battery value below 2.5 gives low battery symbol(BAT_50 or BAT_LOW...same thing defined)

	}


//LCD clear routine
void LCD_all_off(void)
{
 LCDM2 = 0x00;
 LCDM3 = 0x00;
 LCDM4 = 0x00;
 LCDM5 = 0x00;
 LCDM6 = 0x00;
 LCDM7 = 0x00;
 LCDM8 = 0x00;
 LCDM9 = 0x00;
 LCDM10 = 0x00;
 LCDM11 = 0x00;
 LCDM12 = 0x00;
 LCDM13 = 0x00;
}

sorry changed it....the type is double not unsigned double...!!

Ok.. I have changed the code totally...to make it more simpler... Few notes ....ADC_value defined should be the value i will get after conversion considering the internal voltage divider of the ADC(ADC12MCTL0=SREF_1+INCH_11; )....now when i get that converted value...as you said i can convert that to voltage...and then use it to find the status of the battery... and then make the comparison..... (BAT_VOLT) defines that...Then that can be used for comparison...!However, still the program just jumps to the BAT_LOW..when ISR is called,...not sure what it is doing??thanks for your time

#include  <msp430fg4618.h>
#include <stdint.h>
#include<intrinsics.h> //For add_bcd_short function to be used
#include  "LCD_defs.h" // P7_A1...P1_A0....all defined here
unsigned int ADCValue;
unsigned int BAT_VOLT;
void LCD_all_off(void);

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

  //LCD_A S0-S21 configuration
            LCDAPCTL0 = LCDS24 | LCDS20 | LCDS16 | LCDS12 | LCDS8 | LCDS4;

            // LCD_A configuration
            LCDACTL = LCDFREQ_192 | LCD4MUX | LCDSON | LCDON;   // (ACLK = 32768)/192, 4-mux LCD, LCD_A on, Segments on
            LCDAVCTL0 = LCDCPEN;                                // Charge pump enable
            LCDAVCTL1 = VLCD_3_44;
            LCD_all_off();

 // ADC CONFIGURATION

  P6SEL |= 0x01;                            // Enable A/D channel A0
  //ADC12CTL0 = ADC12ON + SHT0_8 + MSC;       // Turn on ADC12, set sampling time
  ADC12CTL0 = REFON + REF2_5V + ADC12ON + SHT0_8+ MSC;//reference used 2.5 v , MSC= multiple sample and conversion starts another
  	  	  	  	  	  	  	  	  	  	  	  	  	  //conversions as one ends// SHT0_8 ..256 cycles of clock
  ADC12CTL1 = SHP + CONSEQ_2;               // Use sampling timer, set mode//repeat single channel conversions
  ADC12IE = 0x01;                           // Enable ADC12IFG.0
  ADC12CTL0 |= ENC; 						 // Enable conversions
  ADC12MCTL0=SREF_1+INCH_11;                    // selecting reference and channel 11(( Avcc-Avss)/2)
  __enable_interrupt();                     // Enable interrupts
  ADC12CTL0 |= ADC12SC;                     // Start conversion
  __bis_SR_register(LPM0_bits);             // LPM0
}

#pragma vector = ADC12_VECTOR
__interrupt void ADC12_ISR(void)
{
ADCValue= ADC12MEM0;  // Move  conversion result, IFG is cleared
BAT_VOLT= (ADCValue)*(2.5/4095) ;   //coverting the value from ADC into voltage

if (BAT_VOLT>=1.25){        //using voltage divide 2.5/2 =1.25 (not sure abt this bit??)
	BAT_FULL;             // Any battery value above 2.5 gives symbol battery full
}else{
		BAT_50;}              //any battery value below 2.5 gives low battery symbol(BAT_50 or BAT_LOW...same thing defined)

	}


//LCD clear routine
void LCD_all_off(void)
{
 LCDM2 = 0x00;
 LCDM3 = 0x00;
 LCDM4 = 0x00;
 LCDM5 = 0x00;
 LCDM6 = 0x00;
 LCDM7 = 0x00;
 LCDM8 = 0x00;
 LCDM9 = 0x00;
 LCDM10 = 0x00;
 LCDM11 = 0x00;
 LCDM12 = 0x00;
 LCDM13 = 0x00;
}