AX12.cpp

00001 /* mbed AX-12+ Servo Library
00002  *
00003  * Copyright (c) 2010, cstyles (http://mbed.org)
00004  *
00005  * Permission is hereby granted, free of charge, to any person obtaining a copy
00006  * of this software and associated documentation files (the "Software"), to deal
00007  * in the Software without restriction, including without limitation the rights
00008  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00009  * copies of the Software, and to permit persons to whom the Software is
00010  * furnished to do so, subject to the following conditions:
00011  *
00012  * The above copyright notice and this permission notice shall be included in
00013  * all copies or substantial portions of the Software.
00014  *
00015  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00016  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00017  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00018  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00019  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00020  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00021  * THE SOFTWARE.
00022  */
00023 
00024 #include "AX12.h"
00025 #include "mbed.h"
00026 
00027 extern Serial logger;
00028 
00029 AX12::AX12(PinName tx, PinName rx, int ID, int baud)
00030         : _ax12(tx,rx) {
00031     _baud = baud;
00032     _ID = ID;
00033     _ax12.baud(_baud);
00034 
00035 }
00036 
00037 // set the mode of the servo
00038 //  0 = Positional (0-300 degrees)
00039 //  1 = Rotational -1 to 1 speed
00040 int AX12::setMode(int mode) {
00041 
00042     if (mode == 1) { // set CR
00043         setCWLimit(0);
00044         setCCWLimit(0);
00045         setCRSpeed(0.0);
00046     } else {
00047         setCWLimit(0);
00048         setCCWLimit(300);
00049         setCRSpeed(0.0);
00050     }
00051     return(0);
00052 }
00053 
00054 
00055 // if flag[0] is set, were blocking
00056 // if flag[1] is set, we're registering
00057 // they are mutually exclusive operations
00058 int AX12::setGoal(int degrees, int flags) {
00059 
00060     char reg_flag = 0;
00061     char data[2];
00062     _goal = degrees;
00063 
00064     // set the flag is only the register bit is set in the flag
00065     if (flags == 0x2) {
00066         reg_flag = 1;
00067     }
00068 
00069     // 1023 / 300 * degrees
00070     short goal = (1023 * degrees) / 300;
00071 #ifdef AX12_DEBUG
00072     logger.printf("setGoal to 0x%x\n",goal);
00073 #endif
00074 
00075     data[0] = goal & 0xff; // bottom 8 bits
00076     data[1] = goal >> 8;   // top 8 bits
00077 
00078     // write the packet, return the error code
00079     int rVal = write(_ID, AX12_REG_GOAL_POSITION, 2, data, reg_flag);
00080 
00081     if (flags == 1) {
00082         // block until it comes to a halt
00083         while (isMoving()) {}
00084     }
00085     return(rVal);
00086 }
00087 
00088 int AX12::setMaxTorque(int maxTorque)
00089 {
00090     char data[2];
00091     
00092     data[0] = maxTorque & 0xFF;
00093     data[1] = maxTorque >> 8;
00094     
00095     // write the packet, return the error code
00096     int rVal = write(_ID, 0x22, 2, data);
00097 
00098     return(rVal);
00099 }
00100 
00101 
00102 // set continuous rotation speed from -1 to 1
00103 int AX12::setCRSpeed(float speed) {
00104 
00105     // bit 10     = direction, 0 = CCW, 1=CW
00106     // bits 9-0   = Speed
00107     char data[2];
00108 
00109     int goal = (0x3ff * abs(speed));
00110 
00111     // set direction CW if we have a negative speed
00112     if (speed < 0) {
00113         goal |= (0x1 << 10);
00114     }
00115 
00116     data[0] = goal & 0xff; // bottom 8 bits
00117     data[1] = goal >> 8;   // top 8 bits
00118 
00119     // write the packet, return the error code
00120     int rVal = write(_ID, 0x20, 2, data);
00121 
00122     return(rVal);
00123 }
00124 
00125 
00126 int AX12::setCWLimit (int degrees) {
00127 
00128     char data[2];
00129 
00130     // 1023 / 300 * degrees
00131     short limit = (1023 * degrees) / 300;
00132 
00133 #ifdef AX12_DEBUG
00134     logger.printf("setCWLimit to 0x%x\n",limit);
00135 #endif
00136 
00137     data[0] = limit & 0xff; // bottom 8 bits
00138     data[1] = limit >> 8;   // top 8 bits
00139 
00140     // write the packet, return the error code
00141     return (write(_ID, AX12_REG_CW_LIMIT, 2, data));
00142 
00143 }
00144 
00145 int AX12::setCCWLimit (int degrees) {
00146 
00147     char data[2];
00148 
00149     // 1023 / 300 * degrees
00150     short limit = (1023 * degrees) / 300;
00151 
00152 #ifdef AX12_DEBUG
00153     logger.printf("setCCWLimit to 0x%x\n",limit);
00154 #endif
00155 
00156     data[0] = limit & 0xff; // bottom 8 bits
00157     data[1] = limit >> 8;   // top 8 bits
00158 
00159     // write the packet, return the error code
00160     return (write(_ID, AX12_REG_CCW_LIMIT, 2, data));
00161 }
00162 
00163 
00164 int AX12::setID (int CurrentID, int NewID) {
00165 
00166     char data[1];
00167     data[0] = NewID;
00168 
00169 #ifdef AX12_DEBUG
00170     logger.printf("setting ID from 0x%x to 0x%x\n",CurrentID,NewID);
00171 #endif
00172 
00173     return (write(CurrentID, AX12_REG_ID, 1, data));
00174 
00175 }
00176 
00177 
00178 int AX12::setBaud (int baud) {
00179 
00180     char data[1];
00181     data[0] = baud;
00182 
00183 #ifdef AX12_DEBUG
00184     logger.printf("setting Baud rate to %d\n",baud);
00185 #endif
00186 
00187     return (write(0xFE, AX12_REG_BAUD, 1, data));
00188 
00189 }
00190 
00191 
00192 
00193 // return 1 is the servo is still in flight
00194 int AX12::isMoving(void) {
00195 
00196     char data[1];
00197     read(_ID,AX12_REG_MOVING,1,data);
00198     return(data[0]);
00199 }
00200 
00201 
00202 void AX12::trigger(void) {
00203 
00204     char TxBuf[16];
00205     char sum = 0;
00206 
00207 #ifdef AX12_TRIGGER_DEBUG
00208     // Build the TxPacket first in RAM, then we'll send in one go
00209     logger.printf("\nTriggered\n");
00210     logger.printf("\nTrigger Packet\n  Header : 0xFF, 0xFF\n");
00211 #endif
00212 
00213     TxBuf[0] = 0xFF;
00214     TxBuf[1] = 0xFF;
00215 
00216     // ID - Broadcast
00217     TxBuf[2] = 0xFE;
00218     sum += TxBuf[2];
00219 
00220 #ifdef AX12_TRIGGER_DEBUG
00221     logger.printf("  ID : %d\n",TxBuf[2]);
00222 #endif
00223 
00224     // Length
00225     TxBuf[3] = 0x02;
00226     sum += TxBuf[3];
00227 
00228 #ifdef AX12_TRIGGER_DEBUG
00229     logger.printf("  Length %d\n",TxBuf[3]);
00230 #endif
00231 
00232     // Instruction - ACTION
00233     TxBuf[4] = 0x04;
00234     sum += TxBuf[4];
00235 
00236 #ifdef AX12_TRIGGER_DEBUG
00237     logger.printf("  Instruction 0x%X\n",TxBuf[5]);
00238 #endif
00239 
00240     // Checksum
00241     TxBuf[5] = 0xFF - sum;
00242 #ifdef AX12_TRIGGER_DEBUG
00243     logger.printf("  Checksum 0x%X\n",TxBuf[5]);
00244 #endif
00245 
00246     // Transmit the packet in one burst with no pausing
00247     for (int i = 0; i < 6 ; i++) {
00248         _ax12.putc(TxBuf[i]);
00249     }
00250 
00251     // This is a broadcast packet, so there will be no reply
00252     return;
00253 }
00254 
00255 
00256 float AX12::getPosition(void) {
00257 
00258 #ifdef AX12_DEBUG
00259     logger.printf("\ngetPosition(%d)",_ID);
00260 #endif
00261 
00262     char data[2];
00263 
00264     int ErrorCode = read(_ID, AX12_REG_POSITION, 2, data);
00265     short position = data[0] + (data[1] << 8);
00266     float angle = (position * 300)/1024;
00267 
00268     return (angle);
00269 }
00270 
00271 
00272 float AX12::getTemp (void) {
00273 
00274 #ifdef AX12_DEBUG
00275     logger.printf("\ngetTemp(%d)",_ID);
00276 #endif
00277 
00278     char data[1];
00279     int ErrorCode = read(_ID, AX12_REG_TEMP, 1, data);
00280     float temp = data[0];
00281     return(temp);
00282 }
00283 
00284 
00285 float AX12::getVolts (void) {
00286 
00287 #ifdef AX12_DEBUG
00288     logger.printf("\ngetVolts(%d)",_ID);
00289 #endif
00290 
00291     char data[1];
00292     int ErrorCode = read(_ID, AX12_REG_VOLTS, 1, data);
00293     float volts = data[0]/10.0;
00294     return(volts);
00295 }
00296 
00297 
00298 int AX12::read(int ID, int start, int bytes, char* data) {
00299 
00300     char PacketLength = 0x4;
00301     char TxBuf[16];
00302     char sum = 0;
00303     char Status[16];
00304 
00305     Status[4] = 0xFE; // return code
00306 
00307 #ifdef AX12_READ_DEBUG
00308     logger.printf("\nread(%d,0x%x,%d,data)\n",ID,start,bytes);
00309 #endif
00310 
00311     // Build the TxPacket first in RAM, then we'll send in one go
00312 #ifdef AX12_READ_DEBUG
00313     logger.printf("\nInstruction Packet\n  Header : 0xFF, 0xFF\n");
00314 #endif
00315 
00316     TxBuf[0] = 0xff;
00317     TxBuf[1] = 0xff;
00318 
00319     // ID
00320     TxBuf[2] = ID;
00321     sum += TxBuf[2];
00322 
00323 #ifdef AX12_READ_DEBUG
00324     logger.printf("  ID : %d\n",TxBuf[2]);
00325 #endif
00326 
00327     // Packet Length
00328     TxBuf[3] = PacketLength;    // Length = 4 ; 2 + 1 (start) = 1 (bytes)
00329     sum += TxBuf[3];            // Accululate the packet sum
00330 
00331 #ifdef AX12_READ_DEBUG
00332     logger.printf("  Length : 0x%x\n",TxBuf[3]);
00333 #endif
00334 
00335     // Instruction - Read
00336     TxBuf[4] = 0x2;
00337     sum += TxBuf[4];
00338 
00339 #ifdef AX12_READ_DEBUG
00340     logger.printf("  Instruction : 0x%x\n",TxBuf[4]);
00341 #endif
00342 
00343     // Start Address
00344     TxBuf[5] = start;
00345     sum += TxBuf[5];
00346 
00347 #ifdef AX12_READ_DEBUG
00348     logger.printf("  Start Address : 0x%x\n",TxBuf[5]);
00349 #endif
00350 
00351     // Bytes to read
00352     TxBuf[6] = bytes;
00353     sum += TxBuf[6];
00354 
00355 #ifdef AX12_READ_DEBUG
00356     logger.printf("  No bytes : 0x%x\n",TxBuf[6]);
00357 #endif
00358 
00359     // Checksum
00360     TxBuf[7] = 0xFF - sum;
00361 #ifdef AX12_READ_DEBUG
00362     logger.printf("  Checksum : 0x%x\n",TxBuf[7]);
00363 #endif
00364 
00365     // Transmit the packet in one burst with no pausing
00366     for (int i = 0; i<8 ; i++) {
00367         _ax12.putc(TxBuf[i]);
00368     }
00369 
00370     // Wait for the bytes to be transmitted
00371     wait (0.00002);
00372 
00373     // Skip if the read was to the broadcast address
00374     if (_ID != 0xFE) {
00375 
00376 
00377 
00378         // response packet is always 6 + bytes
00379         // 0xFF, 0xFF, ID, Length Error, Param(s) Checksum
00380         // timeout is a little more than the time to transmit
00381         // the packet back, i.e. (6+bytes)*10 bit periods
00382 
00383         int timeout = 0;
00384         int plen = 0;
00385         while ((timeout < ((6+bytes)*10)) && (plen<(6+bytes))) {
00386 
00387             if (_ax12.readable()) {
00388                 Status[plen] = _ax12.getc();
00389                 plen++;
00390                 timeout = 0;
00391             }
00392 
00393             // wait for the bit period
00394             wait (1.0/_baud);
00395             timeout++;
00396         }
00397 
00398         if (timeout == ((6+bytes)*10) ) {
00399             return(-1);
00400         }
00401 
00402         // Copy the data from Status into data for return
00403         for (int i=0; i < Status[3]-2 ; i++) {
00404             data[i] = Status[5+i];
00405         }
00406 
00407 #ifdef AX12_READ_DEBUG
00408         logger.printf("\nStatus Packet\n");
00409         logger.printf("  Header : 0x%x\n",Status[0]);
00410         logger.printf("  Header : 0x%x\n",Status[1]);
00411         logger.printf("  ID : 0x%x\n",Status[2]);
00412         logger.printf("  Length : 0x%x\n",Status[3]);
00413         logger.printf("  Error Code : 0x%x\n",Status[4]);
00414 
00415         for (int i=0; i < Status[3]-2 ; i++) {
00416             logger.printf("  Data : 0x%x\n",Status[5+i]);
00417         }
00418 
00419         logger.printf("  Checksum : 0x%x\n",Status[5+(Status[3]-2)]);
00420 #endif
00421 
00422     } // if (ID!=0xFE)
00423 
00424     return(Status[4]);
00425 }
00426 
00427 
00428 int AX12::write(int ID, int start, int bytes, char* data, int flag) {
00429 // 0xff, 0xff, ID, Length, Intruction(write), Address, Param(s), Checksum
00430 
00431     char TxBuf[16];
00432     char sum = 0;
00433     char Status[6];
00434 
00435 #ifdef AX12_WRITE_DEBUG
00436     logger.printf("\nwrite(%d,0x%x,%d,data,%d)\n",ID,start,bytes,flag);
00437 #endif
00438 
00439     // Build the TxPacket first in RAM, then we'll send in one go
00440 #ifdef AX12_WRITE_DEBUG
00441     logger.printf("\nInstruction Packet\n  Header : 0xFF, 0xFF\n");
00442 #endif
00443 
00444     TxBuf[0] = 0xff;
00445     TxBuf[1] = 0xff;
00446 
00447     // ID
00448     TxBuf[2] = ID;
00449     sum += TxBuf[2];
00450 
00451 #ifdef AX12_WRITE_DEBUG
00452     logger.printf("  ID : %d\n",TxBuf[2]);
00453 #endif
00454 
00455     // packet Length
00456     TxBuf[3] = 3+bytes;
00457     sum += TxBuf[3];
00458 
00459 #ifdef AX12_WRITE_DEBUG
00460     logger.printf("  Length : %d\n",TxBuf[3]);
00461 #endif
00462 
00463     // Instruction
00464     if (flag == 1) {
00465         TxBuf[4]=0x04;
00466         sum += TxBuf[4];
00467     } else {
00468         TxBuf[4]=0x03;
00469         sum += TxBuf[4];
00470     }
00471 
00472 #ifdef AX12_WRITE_DEBUG
00473     logger.printf("  Instruction : 0x%x\n",TxBuf[4]);
00474 #endif
00475 
00476     // Start Address
00477     TxBuf[5] = start;
00478     sum += TxBuf[5];
00479 
00480 #ifdef AX12_WRITE_DEBUG
00481     logger.printf("  Start : 0x%x\n",TxBuf[5]);
00482 #endif
00483 
00484     // data
00485     for (char i=0; i<bytes ; i++) {
00486         TxBuf[6+i] = data[i];
00487         sum += TxBuf[6+i];
00488 
00489 #ifdef AX12_WRITE_DEBUG
00490         logger.printf("  Data : 0x%x\n",TxBuf[6+i]);
00491 #endif
00492 
00493     }
00494 
00495     // checksum
00496     TxBuf[6+bytes] = 0xFF - sum;
00497 
00498 #ifdef AX12_WRITE_DEBUG
00499     logger.printf("  Checksum : 0x%x\n",TxBuf[6+bytes]);
00500 #endif
00501 
00502     // Transmit the packet in one burst with no pausing
00503     for (int i = 0; i < (7 + bytes) ; i++) {
00504         _ax12.putc(TxBuf[i]);
00505     }
00506 
00507     // Wait for data to transmit
00508     wait (0.00002);
00509 
00510     // make sure we have a valid return
00511     Status[4]=0x00;
00512 
00513     // we'll only get a reply if it was not broadcast
00514     if (_ID!=0xFE) {
00515 
00516 
00517         // response packet is always 6 bytes
00518         // 0xFF, 0xFF, ID, Length Error, Param(s) Checksum
00519         // timeout is a little more than the time to transmit
00520         // the packet back, i.e. 60 bit periods, round up to 100
00521         int timeout = 0;
00522         int plen = 0;
00523         while ((timeout < 100) && (plen<6)) {
00524 
00525             if (_ax12.readable()) {
00526                 Status[plen] = _ax12.getc();
00527                 plen++;
00528                 timeout = 0;
00529             }
00530 
00531             // wait for the bit period
00532             wait (1.0/_baud);
00533             timeout++;
00534         }
00535 
00536 
00537         // Build the TxPacket first in RAM, then we'll send in one go
00538 #ifdef AX12_WRITE_DEBUG
00539         logger.printf("\nStatus Packet\n  Header : 0x%X, 0x%X\n",Status[0],Status[1]);
00540         logger.printf("  ID : %d\n",Status[2]);
00541         logger.printf("  Length : %d\n",Status[3]);
00542         logger.printf("  Error : 0x%x\n",Status[4]);
00543         logger.printf("  Checksum : 0x%x\n",Status[5]);
00544 #endif
00545 
00546 
00547     }
00548 
00549     return(Status[4]); // return error code
00550 }