1 | //******************************************************************************
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2 | // MSP430x26x Demo - ADC12, Sample A10 Temp and Convert to oC and oF
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3 | //
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4 | // Description: A single sample is made on A10 with reference to internal
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5 | // 1.5V Vref. Software sets ADC12SC to start sample and conversion - ADC12SC
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6 | // automatically cleared at EOC. ADC12 internal oscillator times sample
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7 | // and conversion. In Mainloop MSP430 waits in LPM0 to save power until
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8 | // ADC10 conversion complete, ADC12_ISR will force exit from any LPMx in
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9 | // Mainloop on reti.
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10 | // ACLK = n/a, MCLK = SMCLK = default DCO ~ 1.045MHz, ADC12CLK = ADC12OSC
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11 | //
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12 | // Uncalibrated temperature measured from device to devive will vary do to
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13 | // slope and offset variance from device to device - please see datasheet.
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14 | //
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15 | // MSP430F261x/241x
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16 | // -----------------
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17 | // /|\| XIN|-
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18 | // | | |
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19 | // --|RST XOUT|-
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20 | // | |
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21 | // |A10 |
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22 | //
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23 | // B. Nisarga
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24 | // Texas Instruments Inc.
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25 | // September 2007
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26 | // Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.42A
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27 | //******************************************************************************
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28 |
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29 | #include <msp430x26x.h>
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30 |
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31 | int long temp;
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32 | int long IntDegF;
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33 | int long IntDegC;
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34 |
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35 | void main(void)
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36 | {
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37 | WDTCTL = WDTPW + WDTHOLD; // Stop WDT
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38 | ADC12CTL0 = SHT0_8 + REFON + ADC12ON; // Internal ref = 1.5V
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39 | ADC12CTL1 = SHP; // enable sample timer
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40 | ADC12MCTL0 = SREF_1 + INCH_10; // ADC i/p ch A10 = temp sense i/p
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41 | ADC12IE = 0x001; // ADC_IFG upon conv result-ADCMEMO
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42 | ADC12CTL0 |= ENC;
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43 |
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44 | while(1)
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45 | {
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46 | ADC12CTL0 |= ADC12SC; // Sampling and conversion start
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47 | _BIS_SR(CPUOFF + GIE); // LPM0 with interrupts enabled
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48 |
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49 | // oF = ((x/4096)*1500mV)-923mV)*1/1.97mV = x*761/4096 - 468
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50 | // IntDegF = (ADC12MEM0 - 2519)* 761/4096
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51 | IntDegF = (temp - 2519) * 761;
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52 | IntDegF = IntDegF / 4096;
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53 |
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54 | // oC = ((x/4096)*1500mV)-986mV)*1/3.55mV = x*423/4096 - 278
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55 | // IntDegC = (ADC12MEM0 - 2692)* 423/4096
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56 | IntDegC = (temp - 2692) * 423;
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57 | IntDegC = IntDegC / 4096;
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58 |
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59 | _NOP(); // << SET BREAKPOINT HERE
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60 | }
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61 | }
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62 |
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63 | #pragma vector=ADC12_VECTOR
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64 | __interrupt void ADC12ISR (void)
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65 | {
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66 | temp = ADC12MEM0; // Move results, IFG is cleared
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67 | _BIC_SR_IRQ(CPUOFF); // Clear CPUOFF bit from 0(SR)
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68 | }
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