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.
