/ - Diff - Colony - Robotics Club

Revision 1418

Added encoder_get_x and encoder_get_v.

use get_v at your own risk
If encoder_read returns -1, this usually means battery is low.
If encoder_read returns a value greater than ENCODER_MAX, this usually means there are physical problems with the encoder.

     	usb_init();
     	encoders_init();
     	int encoder_left,encoder_right;
     	int dx_left, dx_right;
     	int x_left, x_right;
     	int v_left, v_right;
     	int tc;
     	while(1) {
     		/* button1 is pressed */
-...
     		usb_puti(encoder_right);
     		usb_puts("\n");
     		dx_left = encoder_get_dx(LEFT);
     		dx_right = encoder_get_dx(RIGHT);
     		x_left = encoder_get_x(LEFT);
     		x_right = encoder_get_x(RIGHT);
     		usb_puts("Total Distance (left, right): ");
     		usb_puti(dx_left);
     		usb_puti(x_left);
     		usb_puts(", ");
     		usb_puti(dx_right);
     		usb_puti(x_right);
     		usb_puts("\n");
     		v_left = encoder_get_v(LEFT);
     		v_right = encoder_get_v(RIGHT);
     		usb_puts("Velocity (left, right): ");
     		usb_puti(v_left);
     		usb_puts(", ");
     		usb_puti(v_right);
     		usb_puts("\n");
     		tc = encoder_get_tc();
     		usb_puts("Time count: ");
     		usb_puti(tc);

     inline unsigned int right_data_array_prev(void);
     inline unsigned int right_data_array_bottom(void);
     //encoder_get_v helper function prototypes
     int left_data_at(int index);
     int right_data_at(int index);
     int get_dx(char encoder, int index);
     void encoder_recv_complete(void){
       	encoder_buf_index = 0;
-...
      * @param encoder this is the encoder that you want to read. Valid arguments
      *          are LEFT and RIGHT
+     *
      * @return the value of the specified encoder
      * @return the value of the specified encoder.
      *         -1 usually means low battery.
      *         values above ENCODER_MAX usually means phyiscal problems with
      *         the encoder.
      **/
     int encoder_read(char encoder){
-...
+    }
     /**
      * @brief Get total distance travelled by the specified encoder (in encoder ticks)
+     *
      * @param encoder the encoder that you want to read, either LEFT or RIGHT
+     *
      * @return The distance covered by the specified encoder.
+     *
      * @note Simply calls encoder_get_dx.
      **/
     int encoder_get_x(char encoder) {
     	return encoder_get_dx(encoder);
+    }
     /**
      * Gets the total distance covered by the specified encoder (in encoder clicks)
+     *
      * @param encoder the encoder that you want to read, use LEFT or RIGHT
-...
     	else return -1;
+    }
     /**
      * @brief Returns the approximated instantaneous velocity of the robot
      * in terms of encoder clicks.
+     *
      * @param encoder RIGHT or LEFT - the wheel you want the velocity for.
+     *
      * @return The instantaneous velocity for the given wheel or twice the ERR_VEL
      *         if an error occurs (1024 * 2 = 2048)
+     *
      * @bug This uses hard coded values and results are inconsistent.
      *      Use at your own risk.
      */
     int encoder_get_v(char encoder){
         int vel1, vel2;
         vel1 = get_dx(encoder, 0);
         vel2 = get_dx(encoder, 1);
         if (vel1 == ERR_VEL && vel2 == ERR_VEL)
             return ERR_VEL << 1;
         else if (vel2 == ERR_VEL)
             return vel1 << 1;
         else if (vel1 == ERR_VEL)
             return vel2 << 1;
         else
             return vel1 + vel2;
+    }
     /**
      * Resets the distance accumulator for the specified
      *  encoder.
-...
     		return right_data_array[right_data_idx + 1];
+    }
     /* Helper functions for encoder_get_v */
     int left_data_at(int index) {
         int tmp_idx = left_data_idx - index;
         if (tmp_idx < 0)
             tmp_idx += BUFFER_SIZE;
         return left_data_array[tmp_idx];
+    }
     int right_data_at(int index) {
         int tmp_idx = right_data_idx - index;
         if (tmp_idx < 0)
             tmp_idx += BUFFER_SIZE;
         return right_data_array[tmp_idx];
+    }
     int get_dx(char encoder, int index) {
         int dx, ctr;
         ctr = 0;
         dx = 1024;
         do {
             if (encoder == LEFT)
                 dx = left_data_at(index+ctr) - left_data_at(index+ctr+38);
             else
                 dx = right_data_at(index+ctr) - right_data_at(index+ctr+38);
             ctr++;
         } while ((dx > 30 || dx < -30) && ctr < 3);
         if (dx > 30 || dx < -30)
             return ERR_VEL;
         return dx;
+    }

     	#define RIGHT 1
     #endif
     /** @brief Max value of valid encoder reading. **/
     #define ENCODER_MAX 1024
     /** @brief Magnet misaligned - likely distance from encoder problem. **/
     #define ENCODER_MAGNET_FAILURE 1025
     /** @brief Encoder misaligned - likely on XY plane. **/
-...
     #define MagDECn _BV(0)
     /** @brief Buffer size **/
     #define BUFFER_SIZE 23
     #define BUFFER_SIZE 46
     #define ERR_VEL 1024
     /** @brief Initialize encoders. **/
     void encoders_init(void);
     /** @brief Read instantaneous encoder value. **/
     int encoder_read(char encoder);
     /** @brief Get total distance traveled.
      *  @note  Simply calls encoder_get_dx.
      **/
     int encoder_get_x(char encoder);
     /** @brief Get instantaneous velocity. **/
     int encoder_get_v(char encoder);
     /** @brief Get total distance traveled. **/
     int encoder_get_dx(char encoder);
     /** @brief Reset distance counter. **/

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Revision 1418