Hi I was trying to move multiple servos using C Language. I modified the code provided in the user manual. I pasted the compact protocol in the manual for moving multiple servos. But it doesn’t work. There are no errors of warnings but the code doesn’t work. I used a serial monitor and took a peek at the serial output and I got this
aa 0c 1f 0d 0a 07 70 2e 70 2e 70 2e 70 2e 70 2e 70 2e 70 2e 70 2e 70 2e 70 2e I don’t know why there is a ‘0d’ in there. Its not supposed to be there. Oh and I am getting the pot position from channel 0 but I cant move the servos. It would be great if you guys can help me with it.
[code]// Uses POSIX functions to send and receive data from a Maestro.
// NOTE: The Maestro’s serial mode must be set to “USB Dual Port”.
// NOTE: You must change the ‘const char * device’ line below.
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#ifdef _WIN32
#define O_NOCTTY 0
#else
#include <termios.h>
#endif
#include <math.h>
int mod (int a, int b)
{
if(b < 0) //you can check for b == 0 separately and do what you want
return mod(-a, -b);
int ret = a % b;
if(ret < 0)
ret+=b;
return ret;
}
// Gets the position of a Maestro channel.
// See the “Serial Servo Commands” section of the user’s guide.
int maestroGetPosition(int fd, unsigned char channel)
{
unsigned char command[] = {170 ,12 ,16 , channel};
if(write(fd, command, sizeof(command)) == -1)
{
perror(“error writing”);
return -1;
}
unsigned char response[2];
if(read(fd,response,2) != 2)
{
perror(“error reading”);
return -1;
}
return response[0] + 256*response[1];
}
// Sets the target of a Maestro channel.
// See the “Serial Servo Commands” section of the user’s guide.
// The units of ‘target’ are quarter-microseconds.
int maestroSetTarget(int fd, unsigned char channel, int target[])
{
unsigned char command[] = {170 ,12 ,31 ,10 ,channel , // 0x9f command, 0x0A numbers of channels to move, channel is the first channel number.
target[1] & 0x7f, target[1] >> 7 & 0x7F, // channe1 pos, channel 1 speed
target[2] & 0x7F, target[2] >> 7 & 0x7F, // …
target[3] & 0x7F, target[3] >> 7 & 0x7F,
target[4] & 0x7F, target[4] >> 7 & 0x7F,
target[5] & 0x7F, target[5] >> 7 & 0x7F,
target[6] & 0x7F, target[6] >> 7 & 0x7F,
target[7] & 0x7F, target[7] >> 7 & 0x7F,
target[8] & 0x7F, target[8] >> 7 & 0x7F,
target[9] & 0x7F, target[9] >> 7 & 0x7F,
target[10] & 0x7F, target[10] >> 7 & 0x7F};// …
if (write(fd, command, sizeof(command)) == -1)
{
perror(“error writing”);
return -1;
}
return 0;
}
int main()
{
// Open the Maestro’s virtual COM port.
const char * device = “\\.\USBSER000”; // Windows, “\\.\COM6” also works
//const char * device = “/dev/ttyACM0”; // Linux
//const char * device = “/dev/cu.usbmodem00034567”; // Mac OS X
int fd = open(device, O_RDWR | O_NOCTTY );
if (fd == -1){
perror(device);
return 1;
}
#ifndef _WIN32
struct termios options;
tcgetattr(fd, &options);
options.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
options.c_oflag &= ~(ONLCR | OCRNL);
tcsetattr(fd, TCSANOW, &options);
#endif
int pot = 0;
int position = maestroGetPosition(fd, pot);
printf(“Current position is %d %d.\n”, position, pot);
int x[10];
x[1] = 6000;
x[2] = 6000;
x[3] = 6000;
x[4] = 6000;
x[5] = 6000;
x[6] = 6000;
x[7] = 6000;
x[8] = 6000;
x[9] = 6000;
x[10] = 6000;
maestroSetTarget(fd,7, x);
close(fd);
return 0;
}
[/code]