/beaglebone_ppm

Library and PRU firmware to read/write PPM protocol on BeagleBone in C

Primary LanguageC

Library and PRU firmware to read/write PPM protocol on BeagleBone black. PPM is commonly used in sending input channel data between RC transmitters, receivers, servos, and flight controllers.

Example usage:

#include "ppm.h"

int main(int argc, char **argv) {
    uint16_t channels[12];
    ppm_t* ppm = ppm_new(PPM_WRONLY);
    if (ppm == NULL) {
        exit(1);
    }

    int i, loop;
    for (loop = 0; ; loop++) {
        for (i=0; i<12; i++) {
            channels[i] = 1000 + 10 * (i+1) + loop;
        }

        ppm_write(ppm, channels);

        sleep(1);
    }
}

TODO: add build and install instructions for PRU firmware.

Notes:

Q: can we package this in such a way that when you use this library, you can easily specify which PRU to run the decoder/encoder on, and which pin is used for as gpio?

perhaps a top-level make command like:

PRU=0 GPIO=P8_45 make decoder

output would then be in gen/decoder_pru0_p8_45.out

then you could use the library like:

 ppm_new(PRU_0, "P8_45", PPM_WRONLY)

Q: do we want to include the .out file in the ppm_new constructor so that we can load it up and reboot it every time we start using the library?

References: