mbed/src/vendor/NXP/capi/i2c_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 "i2c_api.h"
  17
  18 #if DEVICE_I2C
  19
  20 #include "cmsis.h"
  21 #include "pinmap.h"
  22 #include "error.h"
  23
  24 #if defined(TARGET_LPC1768) || defined(TARGET_LPC2368)
  25 static const PinMap PinMap_I2C_SDA[] = {
  26     {P0_0 , I2C_1, 3},
  27     {P0_10, I2C_2, 2},
  28     {P0_19, I2C_1, 3},
  29     {P0_27, I2C_0, 1},
  30     {NC   , NC   , 0}
  31 };
  32
  33 static const PinMap PinMap_I2C_SCL[] = {
  34     {P0_1 , I2C_1, 3},
  35     {P0_11, I2C_2, 2},
  36     {P0_20, I2C_1, 3},
  37     {P0_28, I2C_0, 1},
  38     {NC   , NC,    0}
  39 };
  40
  41 #define I2C_CONSET(x)       (x->i2c->I2CONSET)
  42 #define I2C_CONCLR(x)       (x->i2c->I2CONCLR)
  43 #define I2C_STAT(x)         (x->i2c->I2STAT)
  44 #define I2C_DAT(x)          (x->i2c->I2DAT)
  45 #define I2C_SCLL(x, val)    (x->i2c->I2SCLL = val)
  46 #define I2C_SCLH(x, val)    (x->i2c->I2SCLH = val)
  47
  48 #elif defined(TARGET_LPC11U24)
  49 static const PinMap PinMap_I2C_SDA[] = {
  50     {P0_5, I2C_0, 1},
  51     {NC  , NC   , 0}
  52 };
  53
  54 static const PinMap PinMap_I2C_SCL[] = {
  55     {P0_4, I2C_0, 1},
  56     {NC  , NC,    0}
  57 };
  58
  59 #define I2C_CONSET(x)       (x->i2c->CONSET)
  60 #define I2C_CONCLR(x)       (x->i2c->CONCLR)
  61 #define I2C_STAT(x)         (x->i2c->STAT)
  62 #define I2C_DAT(x)          (x->i2c->DAT)
  63 #define I2C_SCLL(x, val)    (x->i2c->SCLL = val)
  64 #define I2C_SCLH(x, val)    (x->i2c->SCLH = val)
  65 #endif
  66
  67 static const uint32_t I2C_addr_offset[2][4] = {
  68     {0x0C, 0x20, 0x24, 0x28},
  69     {0x30, 0x34, 0x38, 0x3C}
  70 };
  71
  72 static void i2c_conclr(i2c_t *obj, int start, int stop, int interrupt, int acknowledge) {
  73     I2C_CONCLR(obj) = (start << 5)
  74                     | (stop << 4)
  75                     | (interrupt << 3)
  76                     | (acknowledge << 2);
  77 }
  78
  79 static void i2c_conset(i2c_t *obj, int start, int stop, int interrupt, int acknowledge) {
  80     I2C_CONSET(obj) = (start << 5)
  81                     | (stop << 4)
  82                     | (interrupt << 3)
  83                     | (acknowledge << 2);
  84 }
  85
  86 // Clear the Serial Interrupt (SI)
  87 static void i2c_clear_SI(i2c_t *obj) {
  88     i2c_conclr(obj, 0, 0, 1, 0);
  89 }
  90
  91 static int i2c_status(i2c_t *obj) {
  92     return I2C_STAT(obj);
  93 }
  94
  95 // Wait until the Serial Interrupt (SI) is set
  96 static int i2c_wait_SI(i2c_t *obj) {
  97     int timeout = 0;
  98     while (!(I2C_CONSET(obj) & (1 << 3))) {
  99         timeout++;
 100         if (timeout > 100000) return -1;
 101     }
 102     return 0;
 103 }
 104
 105 static void i2c_interface_enable(i2c_t *obj) {
 106     I2C_CONSET(obj) = 0x40;
 107 }
 108
 109 static void i2c_power_enable(i2c_t *obj) {
 110 #if defined(TARGET_LPC1768) || defined(TARGET_LPC2368)
 111     switch ((int)obj->i2c) {
 112         case I2C_0: LPC_SC->PCONP |= 1 << 7; break;
 113         case I2C_1: LPC_SC->PCONP |= 1 << 19; break;
 114         case I2C_2: LPC_SC->PCONP |= 1 << 26; break;
 115     }
 116 #elif defined(TARGET_LPC11U24)
 117     LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 5);
 118     LPC_SYSCON->PRESETCTRL |= 1 << 1;
 119 #endif
 120 }
 121
 122 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
 123     // determine the SPI to use
 124     I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
 125     I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL);
 126 #if defined(TARGET_LPC1768) || defined(TARGET_LPC2368)
 127     obj->i2c = (LPC_I2C_TypeDef *)pinmap_merge(i2c_sda, i2c_scl);
 128 #elif defined(TARGET_LPC11U24)
 129     obj->i2c = (LPC_I2C_Type *)pinmap_merge(i2c_sda, i2c_scl);
 130 #endif
 131     if ((int)obj->i2c == NC) {
 132         error("I2C pin mapping failed");
 133     }
 134
 135     // enable power
 136     i2c_power_enable(obj);
 137
 138     // set default frequency at 100k
 139     i2c_frequency(obj, 100000);
 140     i2c_conclr(obj, 1, 1, 1, 1);
 141     i2c_interface_enable(obj);
 142
 143     pinmap_pinout(sda, PinMap_I2C_SDA);
 144     pinmap_pinout(scl, PinMap_I2C_SCL);
 145 }
 146
 147 int i2c_start(i2c_t *obj) {
 148     int status;
 149
 150     // 8.1 Before master mode can be entered, I2CON must be initialised to:
 151     //  - I2EN STA STO SI AA - -
 152     //  -  1    0   0   0  x - -
 153     // if AA = 0, it can't enter slave mode
 154     i2c_conclr(obj, 1, 1, 1, 1);
 155
 156     // The master mode may now be entered by setting the STA bit
 157     // this will generate a start condition when the bus becomes free
 158     i2c_conset(obj, 1, 0, 0, 1);
 159
 160     i2c_wait_SI(obj);
 161     status = i2c_status(obj);
 162
 163     // Clear start bit now transmitted, and interrupt bit
 164     i2c_conclr(obj, 1, 0, 0, 0);
 165
 166     return status;
 167 }
 168
 169 void i2c_stop(i2c_t *obj) {
 170     // write the stop bit
 171     i2c_conset(obj, 0, 1, 0, 0);
 172     i2c_clear_SI(obj);
 173
 174     // wait for STO bit to reset
 175     while(I2C_CONSET(obj) & (1 << 4));
 176 }
 177
 178
 179 static int i2c_do_write(i2c_t *obj, int value) {
 180     // write the data
 181     I2C_DAT(obj) = value;
 182
 183     // clear SI to init a send
 184     i2c_clear_SI(obj);
 185
 186     i2c_wait_SI(obj);
 187     // wait and return status
 188     return i2c_status(obj);
 189 }
 190
 191 static int i2c_do_read(i2c_t *obj, int last) {
 192     // we are in state 0x40 (SLA+R tx'd) or 0x50 (data rx'd and ack)
 193
 194     if(last) {
 195         i2c_conclr(obj, 0, 0, 0, 1); // send a NOT ACK
 196     } else {
 197         i2c_conset(obj, 0, 0, 0, 1); // send a ACK
 198     }
 199
 200     // accept byte
 201     i2c_clear_SI(obj);
 202
 203     // wait for it to arrive
 204     i2c_wait_SI(obj);
 205
 206     // return the data
 207     return (I2C_DAT(obj) & 0xFF);
 208 }
 209
 210 void i2c_frequency(i2c_t *obj, int hz) {
 211 #if defined(TARGET_LPC1768) || defined(TARGET_LPC2368)
 212     // [TODO] set pclk to /4
 213     uint32_t PCLK = SystemCoreClock / 4;
 214 #elif defined(TARGET_LPC11U24)
 215     // No peripheral clock divider on the M0
 216     uint32_t PCLK = SystemCoreClock;
 217 #endif
 218
 219     uint32_t pulse = PCLK / (hz * 2);
 220
 221     // I2C Rate
 222     I2C_SCLL(obj, pulse);
 223     I2C_SCLH(obj, pulse);
 224 }
 225
 226 // The I2C does a read or a write as a whole operation
 227 // There are two types of error conditions it can encounter
 228 //  1) it can not obtain the bus
 229 //  2) it gets error responses at part of the transmission
 230 //
 231 // We tackle them as follows:
 232 //  1) we retry until we get the bus. we could have a "timeout" if we can not get it
 233 //      which basically turns it in to a 2)
 234 //  2) on error, we use the standard error mechanisms to report/debug
 235 //
 236 // Therefore an I2C transaction should always complete. If it doesn't it is usually
 237 // because something is setup wrong (e.g. wiring), and we don't need to programatically
 238 // check for that
 239
 240 int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
 241     int count, status;
 242
 243     status = i2c_start(obj);
 244
 245     if ((status != 0x10) && (status != 0x08)) {
 246         i2c_stop(obj);
 247         return status;
 248     }
 249
 250     status = i2c_do_write(obj, (address | 0x01));
 251     if (status != 0x40) {
 252         i2c_stop(obj);
 253         return status;
 254     }
 255
 256     // Read in all except last byte
 257     for (count = 0; count < (length - 1); count++) {
 258         int value = i2c_do_read(obj, 0);
 259         status = i2c_status(obj);
 260         if (status != 0x50) {
 261             i2c_stop(obj);
 262             return status;
 263         }
 264         data[count] = (char) value;
 265     }
 266
 267     // read in last byte
 268     int value = i2c_do_read(obj, 1);
 269     status = i2c_status(obj);
 270     if (status != 0x58) {
 271         i2c_stop(obj);
 272         return status;
 273     }
 274
 275     data[count] = (char) value;
 276
 277     // If not repeated start, send stop.
 278     if (stop) {
 279         i2c_stop(obj);
 280     }
 281
 282     return 0;
 283 }
 284
 285 int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
 286     int i, status;
 287
 288     status = i2c_start(obj);
 289
 290     if ((status != 0x10) && (status != 0x08)) {
 291         i2c_stop(obj);
 292         return status;
 293     }
 294
 295     status = i2c_do_write(obj, (address & 0xFE));
 296     if (status != 0x18) {
 297         i2c_stop(obj);
 298         return status;
 299     }
 300
 301     for (i=0; i<length; i++) {
 302         status = i2c_do_write(obj, data[i]);
 303         if(status != 0x28) {
 304             i2c_stop(obj);
 305             return status;
 306         }
 307     }
 308
 309     i2c_clear_SI(obj);
 310
 311     if (stop) {
 312         i2c_stop(obj);
 313     }
 314
 315     return 0;
 316 }
 317
 318 void i2c_reset(i2c_t *obj) {
 319     i2c_stop(obj);
 320 }
 321
 322 int i2c_byte_read(i2c_t *obj, int last) {
 323     return (i2c_do_read(obj, last) & 0xFF);
 324 }
 325
 326 int i2c_byte_write(i2c_t *obj, int data) {
 327     int ack;
 328     int status = i2c_do_write(obj, (data & 0xFF));
 329
 330     switch(status) {
 331         case 0x18: case 0x28:       // Master transmit ACKs
 332             ack = 1;
 333             break;
 334         case 0x40:                  // Master receive address transmitted ACK
 335             ack = 1;
 336             break;
 337         case 0xB8:                  // Slave transmit ACK
 338             ack = 1;
 339             break;
 340         default:
 341             ack = 0;
 342             break;
 343     }
 344
 345     return ack;
 346 }
 347
 348 #if DEVICE_I2CSLAVE
 349 void i2c_slave_mode(i2c_t *obj, int enable_slave) {
 350     if (enable_slave != 0) {
 351         i2c_conclr(obj, 1, 1, 1, 0);
 352         i2c_conset(obj, 0, 0, 0, 1);
 353     } else {
 354         i2c_conclr(obj, 1, 1, 1, 1);
 355     }
 356 }
 357
 358 int i2c_slave_receive(i2c_t *obj) {
 359     int status;
 360     int retval;
 361
 362     status = i2c_status(obj);
 363     switch(status) {
 364         case 0x60: retval = 3; break;
 365         case 0x70: retval = 2; break;
 366         case 0xA8: retval = 1; break;
 367         default  : retval = 0; break;
 368     }
 369
 370     return(retval);
 371 }
 372
 373 int i2c_slave_read(i2c_t *obj, char *data, int length) {
 374     int count = 0;
 375     int status;
 376
 377     do {
 378         i2c_clear_SI(obj);
 379         i2c_wait_SI(obj);
 380         status = i2c_status(obj);
 381         if((status == 0x80) || (status == 0x90)) {
 382             data[count] = I2C_DAT(obj) & 0xFF;
 383         }
 384         count++;
 385     } while (((status == 0x80) || (status == 0x90) ||
 386             (status == 0x060) || (status == 0x70)) && (count < length));
 387
 388     if(status != 0xA0) {
 389         i2c_stop(obj);
 390     }
 391
 392     i2c_clear_SI(obj);
 393
 394     return (count - 1);
 395 }
 396
 397 int i2c_slave_write(i2c_t *obj, const char *data, int length) {
 398     int count = 0;
 399     int status;
 400
 401     if(length <= 0) {
 402         return(0);
 403     }
 404
 405     do {
 406         status = i2c_do_write(obj, data[count]);
 407         count++;
 408     } while ((count < length) && (status == 0xB8));
 409
 410     if((status != 0xC0) && (status != 0xC8)) {
 411         i2c_stop(obj);
 412     }
 413
 414     i2c_clear_SI(obj);
 415
 416     return(count);
 417 }
 418
 419 void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask) {
 420     uint32_t addr;
 421
 422     if ((idx >= 0) && (idx <= 3)) {
 423         addr = ((uint32_t)obj->i2c) + I2C_addr_offset[0][idx];
 424         *((uint32_t *) addr) = address & 0xFF;
 425 #ifdef TARGET_LPC1768
 426         addr = ((uint32_t)obj->i2c) + I2C_addr_offset[1][idx];
 427         *((uint32_t *) addr) = mask & 0xFE;
 428 #endif
 429     }
 430 }
 431 #endif
 432
 433 #endif