CAN_com.cpp

00001 #include "CAN_com.h"
00002 
00003 
00004  #define P_MIN -12.5f
00005  #define P_MAX 12.5f
00006  #define V_MIN -45.0f
00007  #define V_MAX 45.0f
00008  #define KP_MIN 0.0f
00009  #define KP_MAX 500.0f
00010  #define KD_MIN 0.0f
00011  #define KD_MAX 5.0f
00012  #define T_MIN -18.0f
00013  #define T_MAX 18.0f
00014  
00015 
00016 /// CAN Reply Packet Structure ///
00017 /// 16 bit position, between -4*pi and 4*pi
00018 /// 12 bit velocity, between -30 and + 30 rad/s
00019 /// 12 bit current, between -40 and 40;
00020 /// CAN Packet is 5 8-bit words
00021 /// Formatted as follows.  For each quantity, bit 0 is LSB
00022 /// 0: [position[15-8]]
00023 /// 1: [position[7-0]] 
00024 /// 2: [velocity[11-4]]
00025 /// 3: [velocity[3-0], current[11-8]]
00026 /// 4: [current[7-0]]
00027 void pack_reply(CANMessage *msg, float p, float v, float t){
00028     int p_int = float_to_uint(p, P_MIN, P_MAX, 16);
00029     int v_int = float_to_uint(v, V_MIN, V_MAX, 12);
00030     int t_int = float_to_uint(t, -T_MAX, T_MAX, 12);
00031     msg->data[0] = CAN_ID;
00032     msg->data[1] = p_int>>8;
00033     msg->data[2] = p_int&0xFF;
00034     msg->data[3] = v_int>>4;
00035     msg->data[4] = ((v_int&0xF)<<4) + (t_int>>8);
00036     msg->data[5] = t_int&0xFF;
00037     }
00038     
00039 /// CAN Command Packet Structure ///
00040 /// 16 bit position command, between -4*pi and 4*pi
00041 /// 12 bit velocity command, between -30 and + 30 rad/s
00042 /// 12 bit kp, between 0 and 500 N-m/rad
00043 /// 12 bit kd, between 0 and 100 N-m*s/rad
00044 /// 12 bit feed forward torque, between -18 and 18 N-m
00045 /// CAN Packet is 8 8-bit words
00046 /// Formatted as follows.  For each quantity, bit 0 is LSB
00047 /// 0: [position[15-8]]
00048 /// 1: [position[7-0]] 
00049 /// 2: [velocity[11-4]]
00050 /// 3: [velocity[3-0], kp[11-8]]
00051 /// 4: [kp[7-0]]
00052 /// 5: [kd[11-4]]
00053 /// 6: [kd[3-0], torque[11-8]]
00054 /// 7: [torque[7-0]]
00055 void unpack_cmd(CANMessage msg, ControllerStruct * controller){
00056         int p_int = (msg.data[0]<<8)|msg.data[1];
00057         int v_int = (msg.data[2]<<4)|(msg.data[3]>>4);
00058         int kp_int = ((msg.data[3]&0xF)<<8)|msg.data[4];
00059         int kd_int = (msg.data[5]<<4)|(msg.data[6]>>4);
00060         int t_int = ((msg.data[6]&0xF)<<8)|msg.data[7];
00061         
00062         controller->p_des = uint_to_float(p_int, P_MIN, P_MAX, 16);
00063         controller->v_des = uint_to_float(v_int, V_MIN, V_MAX, 12);
00064         controller->kp = uint_to_float(kp_int, KP_MIN, KP_MAX, 12);
00065         controller->kd = uint_to_float(kd_int, KD_MIN, KD_MAX, 12);
00066         controller->t_ff = uint_to_float(t_int, T_MIN, T_MAX, 12);
00067     //printf("Received   ");
00068     //printf("%.3f  %.3f  %.3f  %.3f  %.3f   %.3f", controller->p_des, controller->v_des, controller->kp, controller->kd, controller->t_ff, controller->i_q_ref);
00069     //printf("\n\r");
00070     }
00071