Hey TJF, When possible, can you tell me something about my results when I got the sample rate using the CAP pin?
Thanks for your attention, Luciano. Sábado, 20 de Dezembro de 2014 20:50:49 UTC, luciano...@gmail.com escreveu: > > Hey TJF, > > I used the CAP pin and I got low values of frequency, using just one ADC, > and it varies. > > > <https://lh6.googleusercontent.com/-1kjRR9O8zlI/VJXf_zzNLMI/AAAAAAAAADY/UOMIBw16jiQ/s1600/1.JPG> > > I think it is because of the printf() function as you refered once. How > can I get the real frequency without using the printf() or an oscilloscope? > And how can I get its minimum, average e maximum? > > This is the code I used. > > -------------------- > #define P1 P9_14 > #define P2 P9_42 > int main(int argc, char **argv) > { > pruIo *Io = pruio_new(PRUIO_DEF_ACTIVE, 0, 0, 0); //! create new > driver structure > > if (Io->Errr) { > printf("initialisation failed (%s)\n", Io->Errr);} > > if (pruio_cap_config(Io, P1, 2.)) { // configure input pin > printf("failed setting input @P_IN (%s)\n", Io->Errr);} > > float f1,d1; > > if (pruio_config(Io, 1, 2 , 0, 4)) { > printf("config failed (%s)\n", Io->Errr);} > > if (pruio_gpio_setValue(Io, P1, 0x8F)) { > printf("failed setting P1 (%s)\n", Io->Errr);} > > while (1) > { > double a= Io->Adc->Value[1]; > > if (a < 25000 ) > { > pruio_gpio_config(Io, P1, 0x8F); > > } > else > { > pruio_gpio_config(Io, P1, 0xF); > > } > if (pruio_cap_Value(Io, P1, &f1, &d1)) { // get > current input > printf("failed reading input @P1 (%s)\n", > Io->Errr); } > > printf("\r Frequency: %10f , Duty: %10f ", > f1, d1); // info > > } > pruio_destroy(Io); > return 0; > } // end of main > > ---------------------- > > Thank you for your attention. > BR, > Luciano. > > Sexta-feira, 19 de Dezembro de 2014 14:22:13 UTC, TJF escreveu: >> >> >> >> Am Mittwoch, 17. Dezember 2014 21:24:46 UTC+1 schrieb >> luciano...@gmail.com: >>> >>> So, if I'm understandig it right, what I conclude is that with only one >>> ADC working, the maximum sample rate we can get is around 93 kHz. >>> >> >> That's wrong. The above snippet is a closed loop control. Its output >> toggles at maximum 93 kHz. This means the controller runs at twice that >> speed (186 kHz). This is 200 kHz ADC sampling rate plus some time to check >> the value and switch the GPIO output. >> >> This additional time varies, depending on the load of the host CPU >> (interrupts handling network, grafics, keyboard, mouse, ...), as you can >> see in the differences between Minimum and Maximum values. If you're going >> to layout a controller, dimension it for the Minimum frequency (in this >> case 120 kHz = 2 * 60 kHz). >> >> BR >> > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
