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anyone?

felipe paulo

anyone?

Not on sunday/weekend. :)

felipe paulo

        ADC10CTL0 |= ENC + ADC10SC;             // Inicia a amostragem/conversão

        volt = ((2.5*conv_ADC10[0])/1023);

Here you start the conversion (setting ADC10SC) and then work with the result. Well, with a result that hasn't appeared yet. An ADC conversion requires some time. Two conversions require twice as much time. You give it no time to do the job.

You'll have to check (worst but simplest case with a busy-waiting while loop) whether the ADC has done its job.

felipe paulo

      ADC10CTL1 = INCH_1 + CONSEQ_1;            // /A2/A1, sequência simples
      ADC10CTL0 = SREF_1 + ADC10SHT_2 + REFON + ADC10ON + ADC10IE + REF2_5V;

I'm not sure whether the ADC likes it when you configure channel and sequence (first line) before you actually switch it on (second line).

felipe paulo

        volt = ((2.5*conv_ADC10[0])/1023);

Using float results in big and slow code. Why not using integer math?
unsigned long int volt = (2500*conv_ADC10[0])>>10;
It gives the voltage in mV, is by magnitudes faster and smaller and,well, the difference between /1023 and /1024 (>>10) is negligible.

felipe paulo

      ADC10CTL0 = SREF_1 + ADC10SHT_2 + REFON + ADC10ON + ADC10IE + REF2_5V;

After switching on the reference, some settling tiem is required. You don't give it the time to settls but almos timmediately start converting,. This results in some (first few) readings being much too high.

Jens-Michael Gross, this some time i can do with __delay_cycles()? Or i have to do with timer?

worked, i change ADC10CTL0 = SREF_1 + ADC10SHT_2 + REFON + ADC10ON + ADC10IE + REF2_5V; TO ADC10CTL0 = SREF_1 + ADC10SHT_2 + REFON + ADC10ON + ADC10IE + MSC + REF2_5V; ..... I do this to measure the power consumer. But to do this i have to multiplicate all points of measure to find the wave of power and after calculate the average power. Do you have some idea how i do this?

felipe paulo

this some time i can do with __delay_cycles()? Or i have to do with timer?

That's your choice. Timers have the advantage that the CPU can do other things while the delay runs. So for more complex projects timer delays are a good thing to have. However, for a first test, delay_cycles is fine. Keep in mind that a timer delay is independent of the CPU execution speed (once the timer is set up once) whiel delay_cycles depends on current CPU cpeed and you'll need to change the parameters everywhere in your code when you change the CPU clock later. Bad thing for code you want to use in different projects.

felipe paulo

I do this to measure the power consumer. But to do this i have to multiplicate all points of measure to find the wave of power and after calculate the average power.

Indeed. Power metering is a lot of math :)
There are different approaches. You can multiply U and I, square it and accumulate it, and after a certain period (e.g. when the voltage crosses zero next time) you divide through the number of measurements and calculate the square root. Then you have the RMS power of this wave. It doesn't take much computing power (except for the square root) and also not much space.
As usual, I suggest fixed point arithmetics rather than using floats. The ADC results are really easy to use as fixed point. Just keep the reference voltage as a scale factor for the final result rather than working with voltage values (your voltage dividers and shunt factors can also applied to the final value rather than to every sample).You can then go with long int calculations all the way until the final square root.

Yes, but how do I get the point of conversion? because the program gives me the result only when the conversion ends. If a can get the points, i can multiply the wave of de voltage and current, find the wave of power and after calculate the average. I don´t know how i do this in the MSP430

I don't really understand what you mean. Sure you can only get the conversion result once it is ready.  One conversion, one 'point'. Available when taken.
It's your programs job to request values when you need them, or take continuously incoming conversions results into a context. Your code just requests one pair of values, then does the calculation and then returns. If this is not what you want, then you need to change the concept of your code.

The DTC can trigger an interrupt whenever a pair of conversions is done, so in an ISR for this interrupt, you can take the two and do whatever you want (multiply, tag them with a timestamp derived from a timer, check for zero-crossing etc.) while the ADC continues making the next sequence of conversions.