temperature demo led display

Here a demo of displaying the Temperature on two digit seven segment LED display, using the CD4511 seven segment display/decoder/driver/latch. I used 6 pins of the MSP430, 4 data bits, two bits for digit select/latch. Have not created a schematic but you can look at a data sheet for the CD4511, I connect the BCD pins in parallel from both CD4511's to the MSP430, Latch pin acts as digit select for writing data.

I used the code from the temperature demo that came with the launchpad, modified it to output to a display.

* Code *

//  MSP430G2231  internal temp senser read

// and display on 7 segment display via 4511 decoder/driver

#include  <msp430x20x2.h>

#include <io.h>

#include <signal.h>

#include <stdlib.h>

#include <stdio.h>

void Initializeports(void);

void ConfigureAdcTempSensor(void);

static void __inline__delay(register unsigned int n);

int display_led(int t);

long tempMeasured[8];

unsigned char tempMeasuredPosition=0;

long tempAverage,tempAverage2;

long tempCalibrated, tempDifference;

void main(void)

  unsigned char i;

  int tc = 0;

  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT

  Initializeports();

  ConfigureAdcTempSensor();

  __enable_interrupt();                     // Enable interrupts.

  /* Main Application Loop */

  while(1)

    ADC10CTL0 |= ENC + ADC10SC;             // Sampling and conversion start

    __bis_SR_register(CPUOFF + GIE);        // LPM0 with interrupts enabled

    /* Moving average filter out of 8 values to somewhat stabilize sampled ADC */

    tempMeasured[tempMeasuredPosition++] = ADC10MEM;

    if (tempMeasuredPosition == 8)

      tempMeasuredPosition = 0;

    tempAverage2 = 0;

    for (i = 0; i < 8; i++)

      tempAverage2 += tempMeasured[i];

    tempAverage2 >>= 3; // Divide by 8 to get average

    tempAverage=tempAverage2; //use temporary avarage to prevent ISRs from using intermediate values

    tc++;

    if (tc > 2000)

display_led( ((tempAverage - 630) * 761) / 1024 );

tc = 0;

int display_led(int t)

int msd, lsd, r1, r2, r3, r4;

// my binary to BCD conversion code, note code expects temp rang not to pass 99 degrees.

// this code can be expanded to do full 16 bit conversion

r2 = t / 10;

r1 = t - r2 * 10;

msd = r2;

lsd = r1;

P1OUT &= ~BIT4; // Select First digit

P1OUT = (BIT0 & msd) | (BIT1 & msd) | (BIT2 & msd) | (BIT3 & msd) | BIT5;  // Output 4 bit BCD code

__inline__delay( 0xff );

P1OUT |= BIT4; // Latch data on first display

P1OUT &= ~BIT5; // Select Second digit

P1OUT = (BIT0 & lsd) | (BIT1 & lsd) | (BIT2 & lsd) | (BIT3 & lsd) | BIT4; // Output 4 bit BCD code

P1OUT |= BIT5;  // Latch data

void Initializeports(void)

P1DIR |= 0x3f;

P1SEL = 0x00;

void ConfigureAdcTempSensor(void)

  unsigned int i;

  /* Configure ADC Temp Sensor Channel */

  ADC10CTL1 = INCH_10 + ADC10DIV_3;         // Temp Sensor ADC10CLK/4

  ADC10CTL0 = SREF_1 + ADC10SHT_3 + REFON + ADC10ON + ADC10IE;

  __inline__delay(0x1000);                     // Wait for ADC Ref to settle

  ADC10CTL0 |= ENC + ADC10SC;               // Sampling and conversion start

  __bis_SR_register(CPUOFF + GIE);          // LPM0 with interrupts enabled

  tempCalibrated = ADC10MEM;

  for (i=0; i < 8; i++)

    tempMeasured[i] = tempCalibrated;

  tempAverage = tempCalibrated;

// Delay Routine from mspgcc help file

static void __inline__delay(register unsigned int n)

  __asm__ __volatile__ (

  "1: \n"

  " dec %[n] \n"

  " jne 1b \n"

        : [n] "+r"(n));

// ADC10 interrupt service routine

interrupt(ADC10_VECTOR) ADC10_ISR (void)

  __bic_SR_register_on_exit(CPUOFF);        // Return to active mode