tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC408X/TARGET_LPC4088/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 "mbed_assert.h"
  17 #include "i2c_api.h"
  18 #include "cmsis.h"
  19 #include "pinmap.h"
  20
  21 static const PinMap PinMap_I2C_SDA[] = {
  22     {P0_0 , I2C_1, 3},
  23     {P0_10, I2C_2, 2},
  24     {P0_19, I2C_1, 3},
  25     {P0_27, I2C_0, 1},
  26     {P1_15, I2C_2, 3},
  27     {P1_30, I2C_0, 4},
  28     {P2_14, I2C_1, 2},
  29     {P2_30, I2C_2, 2},
  30     {P4_20, I2C_2, 4},
  31     {P5_2,  I2C_0, 5},
  32     {NC   , NC   , 0}
  33 };
  34
  35 static const PinMap PinMap_I2C_SCL[] = {
  36     {P0_1 , I2C_1, 3},
  37     {P0_11, I2C_2, 2},
  38     {P0_20, I2C_1, 3},
  39     {P0_28, I2C_0, 1},
  40     {P1_31, I2C_0, 4},
  41     {P2_15, I2C_1, 2},
  42     {P2_31, I2C_2, 2},
  43     {P4_21, I2C_2, 2},
  44     {P4_29, I2C_2, 4},
  45     {P5_3,  I2C_0, 5},
  46     {NC   , NC,    0}
  47 };
  48
  49 #define I2C_CONSET(x)       (x->i2c->CONSET)
  50 #define I2C_CONCLR(x)       (x->i2c->CONCLR)
  51 #define I2C_STAT(x)         (x->i2c->STAT)
  52 #define I2C_DAT(x)          (x->i2c->DAT)
  53 #define I2C_SCLL(x, val)    (x->i2c->SCLL = val)
  54 #define I2C_SCLH(x, val)    (x->i2c->SCLH = val)
  55
  56 static const uint32_t I2C_addr_offset[2][4] = {
  57     {0x0C, 0x20, 0x24, 0x28},
  58     {0x30, 0x34, 0x38, 0x3C}
  59 };
  60
  61 static inline void i2c_conclr(i2c_t *obj, int start, int stop, int interrupt, int acknowledge) {
  62     I2C_CONCLR(obj) = (start << 5)
  63                     | (stop << 4)
  64                     | (interrupt << 3)
  65                     | (acknowledge << 2);
  66 }
  67
  68 static inline void i2c_conset(i2c_t *obj, int start, int stop, int interrupt, int acknowledge) {
  69     I2C_CONSET(obj) = (start << 5)
  70                     | (stop << 4)
  71                     | (interrupt << 3)
  72                     | (acknowledge << 2);
  73 }
  74
  75 // Clear the Serial Interrupt (SI)
  76 static inline void i2c_clear_SI(i2c_t *obj) {
  77     i2c_conclr(obj, 0, 0, 1, 0);
  78 }
  79
  80 static inline int i2c_status(i2c_t *obj) {
  81     return I2C_STAT(obj);
  82 }
  83
  84 // Wait until the Serial Interrupt (SI) is set
  85 static int i2c_wait_SI(i2c_t *obj) {
  86     int timeout = 0;
  87     while (!(I2C_CONSET(obj) & (1 << 3))) {
  88         timeout++;
  89         if (timeout > 100000) return -1;
  90     }
  91     return 0;
  92 }
  93
  94 static inline void i2c_interface_enable(i2c_t *obj) {
  95     I2C_CONSET(obj) = 0x40;
  96 }
  97
  98 static inline void i2c_power_enable(i2c_t *obj) {
  99     switch ((int)obj->i2c) {
 100         case I2C_0: LPC_SC->PCONP |= 1 << 7; break;
 101         case I2C_1: LPC_SC->PCONP |= 1 << 19; break;
 102         case I2C_2: LPC_SC->PCONP |= 1 << 26; break;
 103     }
 104 }
 105
 106 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
 107     // determine the SPI to use
 108     I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
 109     I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL);
 110     obj->i2c = (LPC_I2C_TypeDef *)pinmap_merge(i2c_sda, i2c_scl);
 111     MBED_ASSERT((int)obj->i2c != NC);
 112
 113     // enable power
 114     i2c_power_enable(obj);
 115
 116     // set default frequency at 100k
 117     i2c_frequency(obj, 100000);
 118     i2c_conclr(obj, 1, 1, 1, 1);
 119     i2c_interface_enable(obj);
 120
 121     pinmap_pinout(sda, PinMap_I2C_SDA);
 122     pinmap_pinout(scl, PinMap_I2C_SCL);
 123
 124     // OpenDrain must explicitly be enabled for p0.0 and p0.1
 125     if (sda == P0_0) {
 126         pin_mode(sda, OpenDrain);
 127     }
 128     if (scl == P0_1) {
 129         pin_mode(scl, OpenDrain);
 130     }
 131
 132 }
 133
 134 inline int i2c_start(i2c_t *obj) {
 135     int status = 0;
 136     // 8.1 Before master mode can be entered, I2CON must be initialised to:
 137     //  - I2EN STA STO SI AA - -
 138     //  -  1    0   0   0  x - -
 139     // if AA = 0, it can't enter slave mode
 140     i2c_conclr(obj, 1, 1, 1, 1);
 141
 142     // The master mode may now be entered by setting the STA bit
 143     // this will generate a start condition when the bus becomes free
 144     i2c_conset(obj, 1, 0, 0, 1);
 145
 146     i2c_wait_SI(obj);
 147     status = i2c_status(obj);
 148
 149     // Clear start bit now transmitted, and interrupt bit
 150     i2c_conclr(obj, 1, 0, 0, 0);
 151     return status;
 152 }
 153
 154 inline int i2c_stop(i2c_t *obj) {
 155     int timeout = 0;
 156
 157     // write the stop bit
 158     i2c_conset(obj, 0, 1, 0, 0);
 159     i2c_clear_SI(obj);
 160
 161     // wait for STO bit to reset
 162     while(I2C_CONSET(obj) & (1 << 4)) {
 163         timeout ++;
 164         if (timeout > 100000) return 1;
 165     }
 166
 167     return 0;
 168 }
 169
 170
 171 static inline int i2c_do_write(i2c_t *obj, int value, uint8_t addr) {
 172     // write the data
 173     I2C_DAT(obj) = value;
 174
 175     // clear SI to init a send
 176     i2c_clear_SI(obj);
 177
 178     // wait and return status
 179     i2c_wait_SI(obj);
 180     return i2c_status(obj);
 181 }
 182
 183 static inline int i2c_do_read(i2c_t *obj, int last) {
 184     // we are in state 0x40 (SLA+R tx'd) or 0x50 (data rx'd and ack)
 185     if(last) {
 186         i2c_conclr(obj, 0, 0, 0, 1); // send a NOT ACK
 187     } else {
 188         i2c_conset(obj, 0, 0, 0, 1); // send a ACK
 189     }
 190
 191     // accept byte
 192     i2c_clear_SI(obj);
 193
 194     // wait for it to arrive
 195     i2c_wait_SI(obj);
 196
 197     // return the data
 198     return (I2C_DAT(obj) & 0xFF);
 199 }
 200
 201 void i2c_frequency(i2c_t *obj, int hz) {
 202     uint32_t PCLK = PeripheralClock;
 203     uint32_t pulse = PCLK / (hz * 2);
 204
 205     // I2C Rate
 206     I2C_SCLL(obj, pulse);
 207     I2C_SCLH(obj, pulse);
 208 }
 209
 210 // The I2C does a read or a write as a whole operation
 211 // There are two types of error conditions it can encounter
 212 //  1) it can not obtain the bus
 213 //  2) it gets error responses at part of the transmission
 214 //
 215 // We tackle them as follows:
 216 //  1) we retry until we get the bus. we could have a "timeout" if we can not get it
 217 //      which basically turns it in to a 2)
 218 //  2) on error, we use the standard error mechanisms to report/debug
 219 //
 220 // Therefore an I2C transaction should always complete. If it doesn't it is usually
 221 // because something is setup wrong (e.g. wiring), and we don't need to programatically
 222 // check for that
 223 int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
 224     int count, status;
 225
 226     status = i2c_start(obj);
 227
 228     if ((status != 0x10) && (status != 0x08)) {
 229         i2c_stop(obj);
 230         return I2C_ERROR_BUS_BUSY;
 231     }
 232
 233     status = i2c_do_write(obj, (address | 0x01), 1);
 234     if (status != 0x40) {
 235         i2c_stop(obj);
 236         return I2C_ERROR_NO_SLAVE;
 237     }
 238
 239     // Read in all except last byte
 240     for (count = 0; count < (length - 1); count++) {
 241         int value = i2c_do_read(obj, 0);
 242         status = i2c_status(obj);
 243         if (status != 0x50) {
 244             i2c_stop(obj);
 245             return count;
 246         }
 247         data[count] = (char) value;
 248     }
 249
 250     // read in last byte
 251     int value = i2c_do_read(obj, 1);
 252     status = i2c_status(obj);
 253     if (status != 0x58) {
 254         i2c_stop(obj);
 255         return length - 1;
 256     }
 257
 258     data[count] = (char) value;
 259
 260     // If not repeated start, send stop.
 261     if (stop) {
 262         i2c_stop(obj);
 263     }
 264
 265     return length;
 266 }
 267
 268 int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
 269     int i, status;
 270
 271     status = i2c_start(obj);
 272
 273     if ((status != 0x10) && (status != 0x08)) {
 274         i2c_stop(obj);
 275         return I2C_ERROR_BUS_BUSY;
 276     }
 277
 278     status = i2c_do_write(obj, (address & 0xFE), 1);
 279     if (status != 0x18) {
 280         i2c_stop(obj);
 281         return I2C_ERROR_NO_SLAVE;
 282     }
 283
 284     for (i=0; i<length; i++) {
 285         status = i2c_do_write(obj, data[i], 0);
 286         if (status != 0x28) {
 287             i2c_stop(obj);
 288             return i;
 289         }
 290     }
 291
 292     // clearing the serial interrupt here might cause an unintended rewrite of the last byte
 293     // see also issue report https://mbed.org/users/mbed_official/code/mbed/issues/1
 294     // i2c_clear_SI(obj);
 295
 296     // If not repeated start, send stop.
 297     if (stop) {
 298         i2c_stop(obj);
 299     }
 300
 301     return length;
 302 }
 303
 304 void i2c_reset(i2c_t *obj) {
 305     i2c_stop(obj);
 306 }
 307
 308 int i2c_byte_read(i2c_t *obj, int last) {
 309     return (i2c_do_read(obj, last) & 0xFF);
 310 }
 311
 312 int i2c_byte_write(i2c_t *obj, int data) {
 313     int ack;
 314     int status = i2c_do_write(obj, (data & 0xFF), 0);
 315
 316     switch(status) {
 317         case 0x18: case 0x28:       // Master transmit ACKs
 318             ack = 1;
 319             break;
 320
 321         case 0x40:                  // Master receive address transmitted ACK
 322             ack = 1;
 323             break;
 324
 325         case 0xB8:                  // Slave transmit ACK
 326             ack = 1;
 327             break;
 328
 329         default:
 330             ack = 0;
 331             break;
 332     }
 333
 334     return ack;
 335 }
 336
 337 void i2c_slave_mode(i2c_t *obj, int enable_slave) {
 338     if (enable_slave != 0) {
 339         i2c_conclr(obj, 1, 1, 1, 0);
 340         i2c_conset(obj, 0, 0, 0, 1);
 341     } else {
 342         i2c_conclr(obj, 1, 1, 1, 1);
 343     }
 344 }
 345
 346 int i2c_slave_receive(i2c_t *obj) {
 347     int status;
 348     int retval;
 349
 350     status = i2c_status(obj);
 351     switch(status) {
 352         case 0x60: retval = 3; break;
 353         case 0x70: retval = 2; break;
 354         case 0xA8: retval = 1; break;
 355         default  : retval = 0; break;
 356     }
 357
 358     return(retval);
 359 }
 360
 361 int i2c_slave_read(i2c_t *obj, char *data, int length) {
 362     int count = 0;
 363     int status;
 364
 365     do {
 366         i2c_clear_SI(obj);
 367         i2c_wait_SI(obj);
 368         status = i2c_status(obj);
 369         if((status == 0x80) || (status == 0x90)) {
 370             data[count] = I2C_DAT(obj) & 0xFF;
 371         }
 372         count++;
 373     } while (((status == 0x80) || (status == 0x90) ||
 374             (status == 0x060) || (status == 0x70)) && (count < length));
 375
 376     if(status != 0xA0) {
 377         i2c_stop(obj);
 378     }
 379
 380     i2c_clear_SI(obj);
 381
 382     return count;
 383 }
 384
 385 int i2c_slave_write(i2c_t *obj, const char *data, int length) {
 386     int count = 0;
 387     int status;
 388
 389     if(length <= 0) {
 390         return(0);
 391     }
 392
 393     do {
 394         status = i2c_do_write(obj, data[count], 0);
 395         count++;
 396     } while ((count < length) && (status == 0xB8));
 397
 398     if((status != 0xC0) && (status != 0xC8)) {
 399         i2c_stop(obj);
 400     }
 401
 402     i2c_clear_SI(obj);
 403
 404     return(count);
 405 }
 406
 407 void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask) {
 408     uint32_t addr;
 409
 410     if ((idx >= 0) && (idx <= 3)) {
 411         addr = ((uint32_t)obj->i2c) + I2C_addr_offset[0][idx];
 412         *((uint32_t *) addr) = address & 0xFF;
 413         addr = ((uint32_t)obj->i2c) + I2C_addr_offset[1][idx];
 414         *((uint32_t *) addr) = mask & 0xFE;
 415     }
 416 }