mbed-os

Fork of mbed-os by erkin yucel

Committer:
elessair
Date:
Sun Oct 23 15:10:02 2016 +0000
Revision:
0:f269e3021894
Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
elessair 0:f269e3021894 1 /* mbed Microcontroller Library
elessair 0:f269e3021894 2 * Copyright (c) 2006-2013 ARM Limited
elessair 0:f269e3021894 3 *
elessair 0:f269e3021894 4 * Licensed under the Apache License, Version 2.0 (the "License");
elessair 0:f269e3021894 5 * you may not use this file except in compliance with the License.
elessair 0:f269e3021894 6 * You may obtain a copy of the License at
elessair 0:f269e3021894 7 *
elessair 0:f269e3021894 8 * http://www.apache.org/licenses/LICENSE-2.0
elessair 0:f269e3021894 9 *
elessair 0:f269e3021894 10 * Unless required by applicable law or agreed to in writing, software
elessair 0:f269e3021894 11 * distributed under the License is distributed on an "AS IS" BASIS,
elessair 0:f269e3021894 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
elessair 0:f269e3021894 13 * See the License for the specific language governing permissions and
elessair 0:f269e3021894 14 * limitations under the License.
elessair 0:f269e3021894 15 */
elessair 0:f269e3021894 16 #include "mbed_assert.h"
elessair 0:f269e3021894 17 #include "i2c_api.h"
elessair 0:f269e3021894 18 #include "cmsis.h"
elessair 0:f269e3021894 19 #include "pinmap.h"
elessair 0:f269e3021894 20 #include "PeripheralPins.h" // For the Peripheral to Pin Definitions found in the individual Target's Platform
elessair 0:f269e3021894 21
elessair 0:f269e3021894 22 #define I2C_CONSET(x) (x->i2c->CONSET)
elessair 0:f269e3021894 23 #define I2C_CONCLR(x) (x->i2c->CONCLR)
elessair 0:f269e3021894 24 #define I2C_STAT(x) (x->i2c->STAT)
elessair 0:f269e3021894 25 #define I2C_DAT(x) (x->i2c->DAT)
elessair 0:f269e3021894 26 #define I2C_SCLL(x, val) (x->i2c->SCLL = val)
elessair 0:f269e3021894 27 #define I2C_SCLH(x, val) (x->i2c->SCLH = val)
elessair 0:f269e3021894 28
elessair 0:f269e3021894 29 static const uint32_t I2C_addr_offset[2][4] = {
elessair 0:f269e3021894 30 {0x0C, 0x20, 0x24, 0x28},
elessair 0:f269e3021894 31 {0x30, 0x34, 0x38, 0x3C}
elessair 0:f269e3021894 32 };
elessair 0:f269e3021894 33
elessair 0:f269e3021894 34 static inline void i2c_conclr(i2c_t *obj, int start, int stop, int interrupt, int acknowledge) {
elessair 0:f269e3021894 35 I2C_CONCLR(obj) = (start << 5)
elessair 0:f269e3021894 36 | (stop << 4)
elessair 0:f269e3021894 37 | (interrupt << 3)
elessair 0:f269e3021894 38 | (acknowledge << 2);
elessair 0:f269e3021894 39 }
elessair 0:f269e3021894 40
elessair 0:f269e3021894 41 static inline void i2c_conset(i2c_t *obj, int start, int stop, int interrupt, int acknowledge) {
elessair 0:f269e3021894 42 I2C_CONSET(obj) = (start << 5)
elessair 0:f269e3021894 43 | (stop << 4)
elessair 0:f269e3021894 44 | (interrupt << 3)
elessair 0:f269e3021894 45 | (acknowledge << 2);
elessair 0:f269e3021894 46 }
elessair 0:f269e3021894 47
elessair 0:f269e3021894 48 // Clear the Serial Interrupt (SI)
elessair 0:f269e3021894 49 static inline void i2c_clear_SI(i2c_t *obj) {
elessair 0:f269e3021894 50 i2c_conclr(obj, 0, 0, 1, 0);
elessair 0:f269e3021894 51 }
elessair 0:f269e3021894 52
elessair 0:f269e3021894 53 static inline int i2c_status(i2c_t *obj) {
elessair 0:f269e3021894 54 return I2C_STAT(obj);
elessair 0:f269e3021894 55 }
elessair 0:f269e3021894 56
elessair 0:f269e3021894 57 // Wait until the Serial Interrupt (SI) is set
elessair 0:f269e3021894 58 static int i2c_wait_SI(i2c_t *obj) {
elessair 0:f269e3021894 59 int timeout = 0;
elessair 0:f269e3021894 60 while (!(I2C_CONSET(obj) & (1 << 3))) {
elessair 0:f269e3021894 61 timeout++;
elessair 0:f269e3021894 62 if (timeout > 100000) return -1;
elessair 0:f269e3021894 63 }
elessair 0:f269e3021894 64 return 0;
elessair 0:f269e3021894 65 }
elessair 0:f269e3021894 66
elessair 0:f269e3021894 67 static inline void i2c_interface_enable(i2c_t *obj) {
elessair 0:f269e3021894 68 I2C_CONSET(obj) = 0x40;
elessair 0:f269e3021894 69 }
elessair 0:f269e3021894 70
elessair 0:f269e3021894 71 static inline void i2c_power_enable(i2c_t *obj) {
elessair 0:f269e3021894 72 LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 5);
elessair 0:f269e3021894 73 LPC_SYSCON->PRESETCTRL |= 1 << 1;
elessair 0:f269e3021894 74 }
elessair 0:f269e3021894 75
elessair 0:f269e3021894 76 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
elessair 0:f269e3021894 77 // determine the SPI to use
elessair 0:f269e3021894 78 I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
elessair 0:f269e3021894 79 I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL);
elessair 0:f269e3021894 80 obj->i2c = (LPC_I2C_Type *)pinmap_merge(i2c_sda, i2c_scl);
elessair 0:f269e3021894 81 MBED_ASSERT((int)obj->i2c != NC);
elessair 0:f269e3021894 82
elessair 0:f269e3021894 83 // enable power
elessair 0:f269e3021894 84 i2c_power_enable(obj);
elessair 0:f269e3021894 85
elessair 0:f269e3021894 86 // set default frequency at 100k
elessair 0:f269e3021894 87 i2c_frequency(obj, 100000);
elessair 0:f269e3021894 88 i2c_conclr(obj, 1, 1, 1, 1);
elessair 0:f269e3021894 89 i2c_interface_enable(obj);
elessair 0:f269e3021894 90
elessair 0:f269e3021894 91 pinmap_pinout(sda, PinMap_I2C_SDA);
elessair 0:f269e3021894 92 pinmap_pinout(scl, PinMap_I2C_SCL);
elessair 0:f269e3021894 93 }
elessair 0:f269e3021894 94
elessair 0:f269e3021894 95 inline int i2c_start(i2c_t *obj) {
elessair 0:f269e3021894 96 int status = 0;
elessair 0:f269e3021894 97 int isInterrupted = I2C_CONSET(obj) & (1 << 3);
elessair 0:f269e3021894 98
elessair 0:f269e3021894 99 // 8.1 Before master mode can be entered, I2CON must be initialised to:
elessair 0:f269e3021894 100 // - I2EN STA STO SI AA - -
elessair 0:f269e3021894 101 // - 1 0 0 x x - -
elessair 0:f269e3021894 102 // if AA = 0, it can't enter slave mode
elessair 0:f269e3021894 103 i2c_conclr(obj, 1, 1, 0, 1);
elessair 0:f269e3021894 104
elessair 0:f269e3021894 105 // The master mode may now be entered by setting the STA bit
elessair 0:f269e3021894 106 // this will generate a start condition when the bus becomes free
elessair 0:f269e3021894 107 i2c_conset(obj, 1, 0, 0, 1);
elessair 0:f269e3021894 108 // Clearing SI bit when it wasn't set on entry can jump past state
elessair 0:f269e3021894 109 // 0x10 or 0x08 and erroneously send uninitialized slave address.
elessair 0:f269e3021894 110 if (isInterrupted)
elessair 0:f269e3021894 111 i2c_clear_SI(obj);
elessair 0:f269e3021894 112
elessair 0:f269e3021894 113 i2c_wait_SI(obj);
elessair 0:f269e3021894 114 status = i2c_status(obj);
elessair 0:f269e3021894 115
elessair 0:f269e3021894 116 // Clear start bit now that it's transmitted
elessair 0:f269e3021894 117 i2c_conclr(obj, 1, 0, 0, 0);
elessair 0:f269e3021894 118 return status;
elessair 0:f269e3021894 119 }
elessair 0:f269e3021894 120
elessair 0:f269e3021894 121 inline int i2c_stop(i2c_t *obj) {
elessair 0:f269e3021894 122 int timeout = 0;
elessair 0:f269e3021894 123
elessair 0:f269e3021894 124 // write the stop bit
elessair 0:f269e3021894 125 i2c_conset(obj, 0, 1, 0, 0);
elessair 0:f269e3021894 126 i2c_clear_SI(obj);
elessair 0:f269e3021894 127
elessair 0:f269e3021894 128 // wait for STO bit to reset
elessair 0:f269e3021894 129 while(I2C_CONSET(obj) & (1 << 4)) {
elessair 0:f269e3021894 130 timeout ++;
elessair 0:f269e3021894 131 if (timeout > 100000) return 1;
elessair 0:f269e3021894 132 }
elessair 0:f269e3021894 133
elessair 0:f269e3021894 134 return 0;
elessair 0:f269e3021894 135 }
elessair 0:f269e3021894 136
elessair 0:f269e3021894 137
elessair 0:f269e3021894 138 static inline int i2c_do_write(i2c_t *obj, int value, uint8_t addr) {
elessair 0:f269e3021894 139 // write the data
elessair 0:f269e3021894 140 I2C_DAT(obj) = value;
elessair 0:f269e3021894 141
elessair 0:f269e3021894 142 // clear SI to init a send
elessair 0:f269e3021894 143 i2c_clear_SI(obj);
elessair 0:f269e3021894 144
elessair 0:f269e3021894 145 // wait and return status
elessair 0:f269e3021894 146 i2c_wait_SI(obj);
elessair 0:f269e3021894 147 return i2c_status(obj);
elessair 0:f269e3021894 148 }
elessair 0:f269e3021894 149
elessair 0:f269e3021894 150 static inline int i2c_do_read(i2c_t *obj, int last) {
elessair 0:f269e3021894 151 // we are in state 0x40 (SLA+R tx'd) or 0x50 (data rx'd and ack)
elessair 0:f269e3021894 152 if (last) {
elessair 0:f269e3021894 153 i2c_conclr(obj, 0, 0, 0, 1); // send a NOT ACK
elessair 0:f269e3021894 154 } else {
elessair 0:f269e3021894 155 i2c_conset(obj, 0, 0, 0, 1); // send a ACK
elessair 0:f269e3021894 156 }
elessair 0:f269e3021894 157
elessair 0:f269e3021894 158 // accept byte
elessair 0:f269e3021894 159 i2c_clear_SI(obj);
elessair 0:f269e3021894 160
elessair 0:f269e3021894 161 // wait for it to arrive
elessair 0:f269e3021894 162 i2c_wait_SI(obj);
elessair 0:f269e3021894 163
elessair 0:f269e3021894 164 // return the data
elessair 0:f269e3021894 165 return (I2C_DAT(obj) & 0xFF);
elessair 0:f269e3021894 166 }
elessair 0:f269e3021894 167
elessair 0:f269e3021894 168 void i2c_frequency(i2c_t *obj, int hz) {
elessair 0:f269e3021894 169 // No peripheral clock divider on the M0
elessair 0:f269e3021894 170 uint32_t PCLK = SystemCoreClock;
elessair 0:f269e3021894 171
elessair 0:f269e3021894 172 uint32_t pulse = PCLK / (hz * 2);
elessair 0:f269e3021894 173
elessair 0:f269e3021894 174 // I2C Rate
elessair 0:f269e3021894 175 I2C_SCLL(obj, pulse);
elessair 0:f269e3021894 176 I2C_SCLH(obj, pulse);
elessair 0:f269e3021894 177 }
elessair 0:f269e3021894 178
elessair 0:f269e3021894 179 // The I2C does a read or a write as a whole operation
elessair 0:f269e3021894 180 // There are two types of error conditions it can encounter
elessair 0:f269e3021894 181 // 1) it can not obtain the bus
elessair 0:f269e3021894 182 // 2) it gets error responses at part of the transmission
elessair 0:f269e3021894 183 //
elessair 0:f269e3021894 184 // We tackle them as follows:
elessair 0:f269e3021894 185 // 1) we retry until we get the bus. we could have a "timeout" if we can not get it
elessair 0:f269e3021894 186 // which basically turns it in to a 2)
elessair 0:f269e3021894 187 // 2) on error, we use the standard error mechanisms to report/debug
elessair 0:f269e3021894 188 //
elessair 0:f269e3021894 189 // Therefore an I2C transaction should always complete. If it doesn't it is usually
elessair 0:f269e3021894 190 // because something is setup wrong (e.g. wiring), and we don't need to programatically
elessair 0:f269e3021894 191 // check for that
elessair 0:f269e3021894 192
elessair 0:f269e3021894 193 int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
elessair 0:f269e3021894 194 int count, status;
elessair 0:f269e3021894 195
elessair 0:f269e3021894 196 status = i2c_start(obj);
elessair 0:f269e3021894 197
elessair 0:f269e3021894 198 if ((status != 0x10) && (status != 0x08)) {
elessair 0:f269e3021894 199 i2c_stop(obj);
elessair 0:f269e3021894 200 return I2C_ERROR_BUS_BUSY;
elessair 0:f269e3021894 201 }
elessair 0:f269e3021894 202
elessair 0:f269e3021894 203 status = i2c_do_write(obj, (address | 0x01), 1);
elessair 0:f269e3021894 204 if (status != 0x40) {
elessair 0:f269e3021894 205 i2c_stop(obj);
elessair 0:f269e3021894 206 return I2C_ERROR_NO_SLAVE;
elessair 0:f269e3021894 207 }
elessair 0:f269e3021894 208
elessair 0:f269e3021894 209 // Read in all except last byte
elessair 0:f269e3021894 210 for (count = 0; count < (length - 1); count++) {
elessair 0:f269e3021894 211 int value = i2c_do_read(obj, 0);
elessair 0:f269e3021894 212 status = i2c_status(obj);
elessair 0:f269e3021894 213 if (status != 0x50) {
elessair 0:f269e3021894 214 i2c_stop(obj);
elessair 0:f269e3021894 215 return count;
elessair 0:f269e3021894 216 }
elessair 0:f269e3021894 217 data[count] = (char) value;
elessair 0:f269e3021894 218 }
elessair 0:f269e3021894 219
elessair 0:f269e3021894 220 // read in last byte
elessair 0:f269e3021894 221 int value = i2c_do_read(obj, 1);
elessair 0:f269e3021894 222 status = i2c_status(obj);
elessair 0:f269e3021894 223 if (status != 0x58) {
elessair 0:f269e3021894 224 i2c_stop(obj);
elessair 0:f269e3021894 225 return length - 1;
elessair 0:f269e3021894 226 }
elessair 0:f269e3021894 227
elessair 0:f269e3021894 228 data[count] = (char) value;
elessair 0:f269e3021894 229
elessair 0:f269e3021894 230 // If not repeated start, send stop.
elessair 0:f269e3021894 231 if (stop) {
elessair 0:f269e3021894 232 i2c_stop(obj);
elessair 0:f269e3021894 233 }
elessair 0:f269e3021894 234
elessair 0:f269e3021894 235 return length;
elessair 0:f269e3021894 236 }
elessair 0:f269e3021894 237
elessair 0:f269e3021894 238 int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
elessair 0:f269e3021894 239 int i, status;
elessair 0:f269e3021894 240
elessair 0:f269e3021894 241 status = i2c_start(obj);
elessair 0:f269e3021894 242
elessair 0:f269e3021894 243 if ((status != 0x10) && (status != 0x08)) {
elessair 0:f269e3021894 244 i2c_stop(obj);
elessair 0:f269e3021894 245 return I2C_ERROR_BUS_BUSY;
elessair 0:f269e3021894 246 }
elessair 0:f269e3021894 247
elessair 0:f269e3021894 248 status = i2c_do_write(obj, (address & 0xFE), 1);
elessair 0:f269e3021894 249 if (status != 0x18) {
elessair 0:f269e3021894 250 i2c_stop(obj);
elessair 0:f269e3021894 251 return I2C_ERROR_NO_SLAVE;
elessair 0:f269e3021894 252 }
elessair 0:f269e3021894 253
elessair 0:f269e3021894 254 for (i=0; i<length; i++) {
elessair 0:f269e3021894 255 status = i2c_do_write(obj, data[i], 0);
elessair 0:f269e3021894 256 if(status != 0x28) {
elessair 0:f269e3021894 257 i2c_stop(obj);
elessair 0:f269e3021894 258 return i;
elessair 0:f269e3021894 259 }
elessair 0:f269e3021894 260 }
elessair 0:f269e3021894 261
elessair 0:f269e3021894 262 // clearing the serial interrupt here might cause an unintended rewrite of the last byte
elessair 0:f269e3021894 263 // see also issue report https://mbed.org/users/mbed_official/code/mbed/issues/1
elessair 0:f269e3021894 264 // i2c_clear_SI(obj);
elessair 0:f269e3021894 265
elessair 0:f269e3021894 266 // If not repeated start, send stop.
elessair 0:f269e3021894 267 if (stop) {
elessair 0:f269e3021894 268 i2c_stop(obj);
elessair 0:f269e3021894 269 }
elessair 0:f269e3021894 270
elessair 0:f269e3021894 271 return length;
elessair 0:f269e3021894 272 }
elessair 0:f269e3021894 273
elessair 0:f269e3021894 274 void i2c_reset(i2c_t *obj) {
elessair 0:f269e3021894 275 i2c_stop(obj);
elessair 0:f269e3021894 276 }
elessair 0:f269e3021894 277
elessair 0:f269e3021894 278 int i2c_byte_read(i2c_t *obj, int last) {
elessair 0:f269e3021894 279 return (i2c_do_read(obj, last) & 0xFF);
elessair 0:f269e3021894 280 }
elessair 0:f269e3021894 281
elessair 0:f269e3021894 282 int i2c_byte_write(i2c_t *obj, int data) {
elessair 0:f269e3021894 283 int ack;
elessair 0:f269e3021894 284 int status = i2c_do_write(obj, (data & 0xFF), 0);
elessair 0:f269e3021894 285
elessair 0:f269e3021894 286 switch(status) {
elessair 0:f269e3021894 287 case 0x18: case 0x28: // Master transmit ACKs
elessair 0:f269e3021894 288 ack = 1;
elessair 0:f269e3021894 289 break;
elessair 0:f269e3021894 290 case 0x40: // Master receive address transmitted ACK
elessair 0:f269e3021894 291 ack = 1;
elessair 0:f269e3021894 292 break;
elessair 0:f269e3021894 293 case 0xB8: // Slave transmit ACK
elessair 0:f269e3021894 294 ack = 1;
elessair 0:f269e3021894 295 break;
elessair 0:f269e3021894 296 default:
elessair 0:f269e3021894 297 ack = 0;
elessair 0:f269e3021894 298 break;
elessair 0:f269e3021894 299 }
elessair 0:f269e3021894 300
elessair 0:f269e3021894 301 return ack;
elessair 0:f269e3021894 302 }
elessair 0:f269e3021894 303
elessair 0:f269e3021894 304 void i2c_slave_mode(i2c_t *obj, int enable_slave) {
elessair 0:f269e3021894 305 if (enable_slave != 0) {
elessair 0:f269e3021894 306 i2c_conclr(obj, 1, 1, 1, 0);
elessair 0:f269e3021894 307 i2c_conset(obj, 0, 0, 0, 1);
elessair 0:f269e3021894 308 } else {
elessair 0:f269e3021894 309 i2c_conclr(obj, 1, 1, 1, 1);
elessair 0:f269e3021894 310 }
elessair 0:f269e3021894 311 }
elessair 0:f269e3021894 312
elessair 0:f269e3021894 313 int i2c_slave_receive(i2c_t *obj) {
elessair 0:f269e3021894 314 int status;
elessair 0:f269e3021894 315 int retval;
elessair 0:f269e3021894 316
elessair 0:f269e3021894 317 status = i2c_status(obj);
elessair 0:f269e3021894 318 switch(status) {
elessair 0:f269e3021894 319 case 0x60: retval = 3; break;
elessair 0:f269e3021894 320 case 0x70: retval = 2; break;
elessair 0:f269e3021894 321 case 0xA8: retval = 1; break;
elessair 0:f269e3021894 322 default : retval = 0; break;
elessair 0:f269e3021894 323 }
elessair 0:f269e3021894 324
elessair 0:f269e3021894 325 return(retval);
elessair 0:f269e3021894 326 }
elessair 0:f269e3021894 327
elessair 0:f269e3021894 328 int i2c_slave_read(i2c_t *obj, char *data, int length) {
elessair 0:f269e3021894 329 int count = 0;
elessair 0:f269e3021894 330 int status;
elessair 0:f269e3021894 331
elessair 0:f269e3021894 332 do {
elessair 0:f269e3021894 333 i2c_clear_SI(obj);
elessair 0:f269e3021894 334 i2c_wait_SI(obj);
elessair 0:f269e3021894 335 status = i2c_status(obj);
elessair 0:f269e3021894 336 if((status == 0x80) || (status == 0x90)) {
elessair 0:f269e3021894 337 data[count] = I2C_DAT(obj) & 0xFF;
elessair 0:f269e3021894 338 }
elessair 0:f269e3021894 339 count++;
elessair 0:f269e3021894 340 } while (((status == 0x80) || (status == 0x90) ||
elessair 0:f269e3021894 341 (status == 0x060) || (status == 0x70)) && (count < length));
elessair 0:f269e3021894 342
elessair 0:f269e3021894 343 if(status != 0xA0) {
elessair 0:f269e3021894 344 i2c_stop(obj);
elessair 0:f269e3021894 345 }
elessair 0:f269e3021894 346
elessair 0:f269e3021894 347 i2c_clear_SI(obj);
elessair 0:f269e3021894 348
elessair 0:f269e3021894 349 return count;
elessair 0:f269e3021894 350 }
elessair 0:f269e3021894 351
elessair 0:f269e3021894 352 int i2c_slave_write(i2c_t *obj, const char *data, int length) {
elessair 0:f269e3021894 353 int count = 0;
elessair 0:f269e3021894 354 int status;
elessair 0:f269e3021894 355
elessair 0:f269e3021894 356 if(length <= 0) {
elessair 0:f269e3021894 357 return(0);
elessair 0:f269e3021894 358 }
elessair 0:f269e3021894 359
elessair 0:f269e3021894 360 do {
elessair 0:f269e3021894 361 status = i2c_do_write(obj, data[count], 0);
elessair 0:f269e3021894 362 count++;
elessair 0:f269e3021894 363 } while ((count < length) && (status == 0xB8));
elessair 0:f269e3021894 364
elessair 0:f269e3021894 365 if((status != 0xC0) && (status != 0xC8)) {
elessair 0:f269e3021894 366 i2c_stop(obj);
elessair 0:f269e3021894 367 }
elessair 0:f269e3021894 368
elessair 0:f269e3021894 369 i2c_clear_SI(obj);
elessair 0:f269e3021894 370
elessair 0:f269e3021894 371 return(count);
elessair 0:f269e3021894 372 }
elessair 0:f269e3021894 373
elessair 0:f269e3021894 374 void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask) {
elessair 0:f269e3021894 375 uint32_t addr;
elessair 0:f269e3021894 376
elessair 0:f269e3021894 377 if ((idx >= 0) && (idx <= 3)) {
elessair 0:f269e3021894 378 addr = ((uint32_t)obj->i2c) + I2C_addr_offset[0][idx];
elessair 0:f269e3021894 379 *((uint32_t *) addr) = address & 0xFF;
elessair 0:f269e3021894 380 }
elessair 0:f269e3021894 381 }