tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC23XX/can_api.c

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #include "mbed_assert.h"
  17 #include "can_api.h"
  18 #include "cmsis.h"
  19 #include "pinmap.h"
  20
  21 #include <math.h>
  22 #include <string.h>
  23
  24 /* Acceptance filter mode in AFMR register */
  25 #define ACCF_OFF                0x01
  26 #define ACCF_BYPASS             0x02
  27 #define ACCF_ON                 0x00
  28 #define ACCF_FULLCAN            0x04
  29
  30 /* There are several bit timing calculators on the internet.
  31 http://www.port.de/engl/canprod/sv_req_form.html
  32 http://www.kvaser.com/can/index.htm
  33 */
  34
  35 static const PinMap PinMap_CAN_RD[] = {
  36     {P0_0 , CAN_1, 1},
  37     {P0_4 , CAN_2, 2},
  38     {P0_21, CAN_1, 3},
  39     {P2_7 , CAN_2, 1},
  40     {NC   , NC   , 0}
  41 };
  42
  43 static const PinMap PinMap_CAN_TD[] = {
  44     {P0_1 , CAN_1, 1},
  45     {P0_5 , CAN_2, 2},
  46     {P0_22, CAN_1, 3},
  47     {P2_8 , CAN_2, 1},
  48     {NC   , NC   , 0}
  49 };
  50
  51 // Type definition to hold a CAN message
  52 struct CANMsg {
  53     unsigned int  reserved1 : 16;
  54     unsigned int  dlc       :  4; // Bits 16..19: DLC - Data Length Counter
  55     unsigned int  reserved0 : 10;
  56     unsigned int  rtr       :  1; // Bit 30: Set if this is a RTR message
  57     unsigned int  type      :  1; // Bit 31: Set if this is a 29-bit ID message
  58     unsigned int  id;             // CAN Message ID (11-bit or 29-bit)
  59     unsigned char data[8];        // CAN Message Data Bytes 0-7
  60 };
  61 typedef struct CANMsg CANMsg;
  62
  63 static uint32_t can_disable(can_t *obj) {
  64     uint32_t sm = obj->dev->MOD;
  65     obj->dev->MOD |= 1;
  66     return sm;
  67 }
  68
  69 static inline void can_enable(can_t *obj) {
  70     if (obj->dev->MOD & 1) {
  71         obj->dev->MOD &= ~(1);
  72     }
  73 }
  74
  75 int can_mode(can_t *obj, CanMode mode) {
  76     return 0; // not implemented
  77 }
  78
  79 int can_filter(can_t *obj, uint32_t id, uint32_t mask, CANFormat format, int32_t handle) {
  80     return 0; // not implemented
  81 }
  82
  83 static int can_pclk(can_t *obj) {
  84     int value = 0;
  85     switch ((int)obj->dev) {
  86         case CAN_1: value = (LPC_SC->PCLKSEL0 & (0x3 << 26)) >> 26; break;
  87         case CAN_2: value = (LPC_SC->PCLKSEL0 & (0x3 << 28)) >> 28; break;
  88     }
  89
  90     switch (value) {
  91         case 1: return 1;
  92         case 2: return 2;
  93         case 3: return 6;
  94         default: return 4;
  95     }
  96 }
  97
  98 // This table has the sampling points as close to 75% as possible. The first
  99 // value is TSEG1, the second TSEG2.
 100 static const int timing_pts[23][2] = {
 101     {0x0, 0x0},      // 2,  50%
 102     {0x1, 0x0},      // 3,  67%
 103     {0x2, 0x0},      // 4,  75%
 104     {0x3, 0x0},      // 5,  80%
 105     {0x3, 0x1},      // 6,  67%
 106     {0x4, 0x1},      // 7,  71%
 107     {0x5, 0x1},      // 8,  75%
 108     {0x6, 0x1},      // 9,  78%
 109     {0x6, 0x2},      // 10, 70%
 110     {0x7, 0x2},      // 11, 73%
 111     {0x8, 0x2},      // 12, 75%
 112     {0x9, 0x2},      // 13, 77%
 113     {0x9, 0x3},      // 14, 71%
 114     {0xA, 0x3},      // 15, 73%
 115     {0xB, 0x3},      // 16, 75%
 116     {0xC, 0x3},      // 17, 76%
 117     {0xD, 0x3},      // 18, 78%
 118     {0xD, 0x4},      // 19, 74%
 119     {0xE, 0x4},      // 20, 75%
 120     {0xF, 0x4},      // 21, 76%
 121     {0xF, 0x5},      // 22, 73%
 122     {0xF, 0x6},      // 23, 70%
 123     {0xF, 0x7},      // 24, 67%
 124 };
 125
 126 static unsigned int can_speed(unsigned int sclk, unsigned int pclk, unsigned int cclk, unsigned char psjw) {
 127     uint32_t    btr;
 128     uint16_t    brp = 0;
 129     uint32_t    calcbit;
 130     uint32_t    bitwidth;
 131     int         hit = 0;
 132     int         bits;
 133
 134     bitwidth = sclk / (pclk * cclk);
 135
 136     brp = bitwidth / 0x18;
 137     while ((!hit) && (brp < bitwidth / 4)) {
 138         brp++;
 139         for (bits = 22; bits > 0; bits--) {
 140             calcbit = (bits + 3) * (brp + 1);
 141             if (calcbit == bitwidth) {
 142                 hit = 1;
 143                 break;
 144             }
 145         }
 146     }
 147
 148     if (hit) {
 149         btr = ((timing_pts[bits][1] << 20) & 0x00700000)
 150             | ((timing_pts[bits][0] << 16) & 0x000F0000)
 151             | ((psjw                << 14) & 0x0000C000)
 152             | ((brp                 <<  0) & 0x000003FF);
 153     } else {
 154         btr = 0xFFFFFFFF;
 155     }
 156
 157     return btr;
 158 }
 159
 160 void can_init(can_t *obj, PinName rd, PinName td) {
 161     CANName can_rd = (CANName)pinmap_peripheral(rd, PinMap_CAN_RD);
 162     CANName can_td = (CANName)pinmap_peripheral(td, PinMap_CAN_TD);
 163     obj->dev = (LPC_CAN_TypeDef *)pinmap_merge(can_rd, can_td);
 164     MBED_ASSERT((int)obj->dev != NC);
 165
 166     switch ((int)obj->dev) {
 167         case CAN_1: LPC_SC->PCONP |= 1 << 13; break;
 168         case CAN_2: LPC_SC->PCONP |= 1 << 14; break;
 169     }
 170
 171     pinmap_pinout(rd, PinMap_CAN_RD);
 172     pinmap_pinout(td, PinMap_CAN_TD);
 173
 174     can_reset(obj);
 175     obj->dev->IER = 0;             // Disable Interrupts
 176     can_frequency(obj, 100000);
 177
 178     LPC_CANAF->AFMR = ACCF_BYPASS; // Bypass Filter
 179 }
 180
 181 void can_free(can_t *obj) {
 182     switch ((int)obj->dev) {
 183         case CAN_1: LPC_SC->PCONP &= ~(1 << 13); break;
 184         case CAN_2: LPC_SC->PCONP &= ~(1 << 14); break;
 185     }
 186 }
 187
 188 int can_frequency(can_t *obj, int f) {
 189     int pclk = can_pclk(obj);
 190     int btr = can_speed(SystemCoreClock, pclk, (unsigned int)f, 1);
 191
 192     if (btr > 0) {
 193         uint32_t modmask = can_disable(obj);
 194         obj->dev->BTR = btr;
 195         obj->dev->MOD = modmask;
 196         return 1;
 197     } else {
 198         return 0;
 199     }
 200 }
 201
 202 int can_write(can_t *obj, CAN_Message msg, int cc) {
 203     unsigned int CANStatus;
 204     CANMsg m;
 205
 206     can_enable(obj);
 207
 208     m.id   = msg.id ;
 209     m.dlc  = msg.len & 0xF;
 210     m.rtr  = msg.type;
 211     m.type = msg.format;
 212     memcpy(m.data, msg.data, msg.len);
 213     const unsigned int *buf = (const unsigned int *)&m;
 214
 215     CANStatus = obj->dev->SR;
 216     if (CANStatus & 0x00000004) {
 217         obj->dev->TFI1 = buf[0] & 0xC00F0000;
 218         obj->dev->TID1 = buf[1];
 219         obj->dev->TDA1 = buf[2];
 220         obj->dev->TDB1 = buf[3];
 221         if (cc) {
 222             obj->dev->CMR = 0x30;
 223         } else {
 224             obj->dev->CMR = 0x21;
 225         }
 226         return 1;
 227
 228     } else if (CANStatus & 0x00000400) {
 229         obj->dev->TFI2 = buf[0] & 0xC00F0000;
 230         obj->dev->TID2 = buf[1];
 231         obj->dev->TDA2 = buf[2];
 232         obj->dev->TDB2 = buf[3];
 233         if (cc) {
 234             obj->dev->CMR = 0x50;
 235         } else {
 236             obj->dev->CMR = 0x41;
 237         }
 238         return 1;
 239
 240     } else if (CANStatus & 0x00040000) {
 241         obj->dev->TFI3 = buf[0] & 0xC00F0000;
 242         obj->dev->TID3 = buf[1];
 243         obj->dev->TDA3 = buf[2];
 244         obj->dev->TDB3 = buf[3];
 245         if (cc) {
 246             obj->dev->CMR = 0x90;
 247         } else {
 248             obj->dev->CMR = 0x81;
 249         }
 250         return 1;
 251     }
 252
 253     return 0;
 254 }
 255
 256 int can_read(can_t *obj, CAN_Message *msg, int handle) {
 257     CANMsg x;
 258     unsigned int *i = (unsigned int *)&x;
 259
 260     can_enable(obj);
 261
 262     if (obj->dev->GSR & 0x1) {
 263         *i++ = obj->dev->RFS;  // Frame
 264         *i++ = obj->dev->RID;  // ID
 265         *i++ = obj->dev->RDA;  // Data A
 266         *i++ = obj->dev->RDB;  // Data B
 267         obj->dev->CMR = 0x04;  // release receive buffer
 268
 269         msg->id     = x.id;
 270         msg->len    = x.dlc;
 271         msg->format = (x.type)? CANExtended : CANStandard;
 272         msg->type   = (x.rtr)?  CANRemote:    CANData;
 273         memcpy(msg->data,x.data,x.dlc);
 274         return 1;
 275     }
 276
 277     return 0;
 278 }
 279
 280 void can_reset(can_t *obj) {
 281     can_disable(obj);
 282     obj->dev->GSR = 0; // Reset error counter when CAN1MOD is in reset
 283 }
 284
 285 unsigned char can_rderror(can_t *obj) {
 286     return (obj->dev->GSR >> 16) & 0xFF;
 287 }
 288
 289 unsigned char can_tderror(can_t *obj) {
 290     return (obj->dev->GSR >> 24) & 0xFF;
 291 }
 292
 293 void can_monitor(can_t *obj, int silent) {
 294     uint32_t mod_mask = can_disable(obj);
 295     if (silent) {
 296         obj->dev->MOD |= (1 << 1);
 297     } else {
 298         obj->dev->MOD &= ~(1 << 1);
 299     }
 300     if (!(mod_mask & 1)) {
 301         can_enable(obj);
 302     }
 303 }