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#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#include <time.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <linux/cp210x.h>
/*
* bit 0: 1 left leg NPN base
* bit 1: 2 left leg PNP base
* bit 2: 4 right leg PNP base
* bit 3: 8 right leg NPN base
*/
#define LEFT_NPN_OFF 0
#define LEFT_NPN_ON 1
#define LEFT_PNP_OFF 2
#define LEFT_PNP_ON 0
#define LEFT_LOW (LEFT_NPN_ON | LEFT_PNP_OFF)
#define LEFT_HI (LEFT_NPN_OFF | LEFT_PNP_ON)
#define LEFT_OFF (LEFT_NPN_OFF | LEFT_PNP_OFF)
#define RIGHT_NPN_OFF 0
#define RIGHT_NPN_ON 8
#define RIGHT_PNP_OFF 4
#define RIGHT_PNP_ON 0
#define RIGHT_LOW (RIGHT_NPN_ON | RIGHT_PNP_OFF)
#define RIGHT_HI (RIGHT_NPN_OFF | RIGHT_PNP_ON)
#define RIGHT_OFF (RIGHT_NPN_OFF | RIGHT_PNP_OFF)
#define FORWARDS (RIGHT_LOW | LEFT_HI)
#define BACKWARDS (RIGHT_HI | LEFT_LOW)
#define OFF (RIGHT_OFF| LEFT_OFF)
#define TIMEOUT 750000 /*75ms */
#define RUN_IN 50
#define RELEASE_TENSION 10
int
drive_motor (int fd, int dir)
{
int i;
if (dir > 0)
{
printf (" Motor forwards\n");
i = FORWARDS;
}
else if (dir < 0)
{
printf (" Motor backwards\n");
i = BACKWARDS;
}
else
{
printf (" Motor off\n");
i = OFF;
}
return ioctl (fd, CPIOC_GPIOSET, &i);
}
int
sensor_led_power (int fd, int on)
{
int i = TIOCM_DTR;
printf (" Rotation sensor power %s\n", on ? "on" : "off");
return ioctl (fd, on ? TIOCMBIS : TIOCMBIC, &i);
}
static int
count_steps (int fd, int count)
{
struct timeval tv, tv_changed, tv_diff;
int cts, old_cts = -1;
int counted = 0;
printf (" Counting %d steps", count);
gettimeofday (&tv_changed, NULL);
while (count)
{
ioctl (fd, TIOCMGET, &cts);
cts &= TIOCM_CTS;
if (cts != old_cts)
{
if (cts)
{
counted++;
count--;
printf (".");
fflush (stdout);
}
gettimeofday (&tv_changed, NULL);
old_cts = cts;
}
gettimeofday (&tv, NULL);
timersub (&tv, &tv_changed, &tv_diff);
if (tv_diff.tv_sec || (tv_diff.tv_usec > TIMEOUT))
break;
}
printf ("%d steps\n", counted);
return counted;
}
static int
drive_motor_home (int fd)
{
int ret;
sensor_led_power (fd, 1);
drive_motor (fd, -1);
ret = count_steps (fd, -1);
drive_motor (fd, 0);
ret -= count_steps (fd, -1);
sensor_led_power (fd, 0);
return ret;
}
static int
drive_motor_count (int fd, int dir, int steps)
{
int ret;
sensor_led_power (fd, 1);
drive_motor (fd, dir);
ret = count_steps (fd, steps);
drive_motor (fd, 0);
ret += count_steps (fd, -1);
sensor_led_power (fd, 0);
return ret;
}
int
main (int argc, char *argv[])
{
int overshoot, guard, pos, wanted, delta;
int fd = open (argv[1], O_RDWR);
if (fd < 0)
return -1;
pos = drive_motor_home (fd);
printf ("Motor was %d steps from home\n", pos);
if (argc == 2)
{
pos = drive_motor_count (fd, 1, RELEASE_TENSION);
printf ("Motor now %d steps from home\n", pos);
return 0;
}
pos = drive_motor_count (fd, 1, RUN_IN);
overshoot = pos - RUN_IN; /*overshot */
wanted = atoi (argv[2]);
delta = wanted - pos;
printf ("Now at %d want %d, delta %d\n", pos, wanted, delta);
guard = overshoot * 3;
if ((delta > -guard) && (delta < guard))
{
printf ("Too close\n");
pos += drive_motor_count (fd, 1, RUN_IN);
delta = wanted - pos;
printf ("Now at %d want %d, delta %d\n", pos, wanted, delta);
}
if (delta < 0)
{
pos -= drive_motor_count (fd, -1, (-delta) - overshoot);
}
else if (delta > 0)
{
pos += drive_motor_count (fd, 1, delta - overshoot);
}
printf ("Wanted %d steps, got %d steps\n", wanted, pos);
return 0;
}
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