rc_test_servos.c

/**
 * @file rc_test_servos.c
 * @example    rc_test_servos
 *
 *
 * Demonstrates use of pru to control servos. This program
 * operates in 4 different modes. See the option list below for how to select an
 * operational mode from the command line. In all modes the power rail is
 * enabled to power the servos and the program will refuse to start unless a
 * charged 2-cell LiPo is plugged into the while balance jack and detected by
 * the ADC.
 *
 * NORM: uses rc_servo_send_pulse_normalized() to set one or all servo
 * positions to a value from -1.5 to 1.5 corresponding to their extended range.
 * -1 to 1 is considered the "safe" normal range as some servos will not go
 * beyond this. Test your servos incrementally to find their safe range.
 *
 * MICROSECONDS: You can also specify your own pulse width in microseconds (us).
 * This uses the rc_servo_send_pulse_us() function.
 *
 * SWEEP: This is intended to gently sweep a servo back and forth about the
 * center position. Specify a range limit as a command line argument as
 * described below. This also uses the rc_servo_send_pulse_normalized()
 * function.
 *
 * RADIO: Uses a single user-selected channel of a DSM radio to control one
 * or all of the servo channels. This is really just for testing, use the
 * rc_dsm_passthrough example for controlling multiple servos, or better yet
 * write an application-specific program for your robot. After all, this program
 * is just for testing!!!!
 *
 * @author     James Strawson
 * @date       3/20/2018
 */

#include <stdio.h>
#include <getopt.h>
#include <stdlib.h> // for atoi
#include <signal.h>
#include <rc/time.h>
#include <rc/adc.h>
#include <rc/dsm.h>
#include <rc/servo.h>

static int running;

typedef enum test_mode_t{
        DISABLED,
        NORM,
        MICROSECONDS,
        SWEEP,
        RADIO
}test_mode_t;


static void __print_usage(void)
{
        printf("\n");
        printf(" Options\n");
        printf(" -c {channel}   Specify one channel from 1-8.\n");
        printf("                Otherwise all channels will be driven equally\n");
        printf(" -f {hz}        Specify pulse frequency, otherwise 50hz is used\n");
        printf(" -p {position}  Drive servo to a position between -1.5 & 1.5\n");
        printf(" -w {width_us}  Send pulse width in microseconds (us)\n");
        printf(" -s {limit}     Sweep servo back/forth between +- limit\n");
        printf("                Limit can be between 0 & 1.5\n");
        printf(" -r {ch}        Use DSM radio channel {ch} to control servo\n");
        printf(" -h             Print this help messege \n\n");
        printf("sample use to center servo channel 1:\n");
        printf("   rc_test_servo -c 1 -p 0.0\n\n");
}

// interrupt handler to catch ctrl-c
static void __signal_handler(__attribute__ ((unused)) int dummy)
{
        running=0;
        return;
}

int main(int argc, char *argv[])
{
        double servo_pos=0;
        double sweep_limit=0;
        uint64_t dsm_nanos=0;
        int width_us=0;
        int ch=0; // channel to test, 0 means all channels
        double direction = 1; // switches between 1 & -1 in sweep mode
        test_mode_t mode = DISABLED; //start mode disabled
        int frequency_hz = 50; // default 50hz frequency to send pulses
        int i, c, radio_ch;

        // parse arguments
        opterr = 0;
        while ((c = getopt(argc, argv, "c:f:p:w:s:r:h")) != -1){
                switch (c){
                // channel option
                case 'c':
                        ch = atoi(optarg);
                        if(ch<RC_SERVO_CH_MIN || ch>RC_SERVO_CH_MAX){
                                fprintf(stderr,"ERROR channel option must be between %d and %d\n", RC_SERVO_CH_MIN, RC_SERVO_CH_MAX);
                                return -1;
                        }
                        break;

                // pulse frequency option
                case 'f':
                        frequency_hz = atoi(optarg);
                        if(frequency_hz<1){
                                fprintf(stderr,"Frequency option must be >=1\n");
                                return -1;
                        }
                        break;

                // position option
                case 'p':
                        // make sure only one mode in requested
                        if(mode!=DISABLED){
                                __print_usage();
                                return -1;
                        }
                        servo_pos = atof(optarg);
                        if(servo_pos>1.5 || servo_pos<-1.5){
                                fprintf(stderr,"Servo position must be from -1.5 to 1.5\n");
                                return -1;
                        }
                        mode = NORM;
                        break;

                // width in microseconds option
                case 'w':
                        // make sure only one mode in requested
                        if(mode!=DISABLED){
                                __print_usage();
                                return -1;
                        }
                        width_us = atof(optarg);
                        if(width_us<10){
                                fprintf(stderr,"ERROR: Width in microseconds must be >10\n");
                                return -1;
                        }
                        mode = MICROSECONDS;
                        break;

                // sweep mode option
                case 's':
                        // make sure only one mode in requested
                        if(mode!=DISABLED){
                                __print_usage();
                                return -1;
                        }
                        sweep_limit = atof(optarg);
                        if(sweep_limit>1.5 || sweep_limit<-1.5){
                                fprintf(stderr,"ERROR: Sweep limit must be from -1.5 to 1.5\n");
                                return -1;
                        }
                        mode = SWEEP;
                        servo_pos = 0.0;
                        break;

                // radio mode option
                case 'r':
                        // make sure only one mode in requested
                        if(mode!=DISABLED){
                                __print_usage();
                                return -1;
                        }
                        radio_ch = atoi(optarg);
                        if(radio_ch<1 || radio_ch>RC_MAX_DSM_CHANNELS){
                                fprintf(stderr,"ERROR radio channel option must be between 1 and %d\n", RC_MAX_DSM_CHANNELS);
                                return -1;
                        }
                        mode = RADIO;
                        break;

                // help mode
                case 'h':
                        __print_usage();
                        return 0;

                default:
                        printf("\nInvalid Argument \n");
                        __print_usage();
                        return -1;
                }
        }

        // if the user didn't give enough arguments, exit
        if(mode==DISABLED){
                fprintf(stderr,"\nNot enough input arguments\n");
                __print_usage();
                return -1;
        }

        // set signal handler so the loop can exit cleanly
        signal(SIGINT, __signal_handler);
        running=1;

        // read adc to make sure battery is connected
        if(rc_adc_init()){
                fprintf(stderr,"ERROR: failed to run rc_adc_init()\n");
                return -1;
        }
        if(rc_adc_batt()<6.0){
                fprintf(stderr,"ERROR: battery disconnected or insufficiently charged to drive servos\n");
                return -1;
        }
        rc_adc_cleanup();

        // initialize PRU
        if(rc_servo_init()) return -1;

        // start radio if necessary
        if(mode==RADIO){
                if(rc_dsm_init()==-1) return -1;
                printf("Waiting for first DSM packet\n");
                fflush(stdout);
                while(rc_dsm_is_new_data()==0){
                        if(running==0) return 0;
                        rc_usleep(50000);
                }
        }

        // turn on power
        printf("Turning On 6V Servo Power Rail\n");
        rc_servo_power_rail_en(1);

        // print out what the program is doing
        printf("\n");
        if(ch==0) printf("Sending on all channels.\n");
        else      printf("Sending only to channel %d.\n", ch);
        switch(mode){
        case NORM:
                printf("Using rc_servo_send_pulse_normalized\n");
                printf("Normalized Signal: %f  Pulse Frequency: %d\n", servo_pos, frequency_hz);
                break;
        case MICROSECONDS:
                printf("Using rc_servo_send_pulse_us\n");
                printf("Pulse_width: %d  Pulse Frequency: %d\n", width_us, frequency_hz);
                break;
        case SWEEP:
                printf("Sweeping servos back/forth between +-%f\n", sweep_limit);
                printf("Pulse Frequency: %d\n", frequency_hz);
                break;
        case RADIO:
                printf("Listening for DSM radio signal\n");
                printf("Pulse Frequency: %d\n", frequency_hz);
                break;
        default:
                // should never get here
                fprintf(stderr,"ERROR invalid mode enum\n");
                return -1;
        }



        // Main loop runs at frequency_hz
        while(running){
                switch(mode){

                case NORM:
                        if(rc_servo_send_pulse_normalized(ch,servo_pos)==-1) return -1;
                        break;

                case MICROSECONDS:
                        if(rc_servo_send_pulse_us(ch, width_us)==-1) return -1;
                        break;

                case SWEEP:
                        // increase or decrease position each loop
                        // scale with frequency
                        servo_pos += direction * sweep_limit / frequency_hz;

                        // reset pulse width at end of sweep
                        if(servo_pos>sweep_limit){
                                servo_pos = sweep_limit;
                                direction = -1;
                        }
                        else if(servo_pos < (-sweep_limit)){
                                servo_pos = -sweep_limit;
                                direction = 1;
                        }
                        // send result
                        if(rc_servo_send_pulse_normalized(ch,servo_pos)==-1) return -1;
                        break;

                case RADIO:
                        dsm_nanos = rc_dsm_nanos_since_last_packet();
                        if(dsm_nanos > 200000000){
                                printf("\rSeconds since last DSM packet: %.2f              ", dsm_nanos/1000000000.0);
                        }
                        else{
                                servo_pos = rc_dsm_ch_normalized(radio_ch);
                                // bound the signal to the escs
                                if(servo_pos<-1.5) servo_pos=-1.5;
                                if(servo_pos>1.5) servo_pos=1.5;

                                // send pulse
                                if(rc_servo_send_pulse_normalized(ch,servo_pos)==-1) return -1;

                                // print info
                                printf("\r");// keep printing on same line
                                // print framerate
                                printf("%d/", rc_dsm_resolution());
                                // print num channels in use
                                printf("%d-ch ", rc_dsm_channels());
                                //print all channels
                                for(i=0; i<rc_dsm_channels(); i++){
                                        printf("%d:% 0.2f ", i+1, rc_dsm_ch_normalized(i+1));
                                }
                        }
                        break;




                default:
                        fprintf(stderr,"ERROR unhandled mode\n");
                        return -1;
                }

                // sleep roughly enough to maintain frequency_hz
                rc_usleep(1000000/frequency_hz);
        }

        rc_usleep(50000);
        // turn off power rail and cleanup
        rc_servo_power_rail_en(0);
        rc_servo_cleanup();
        rc_dsm_cleanup();
        return 0;
}