Lee Kai Xuan / mbed-os

mbed-os

Fork of mbed-os by erkin yucel

targets/TARGET_Freescale/TARGET_K20XX/i2c_api.c@0:f269e3021894, 2016-10-23 (annotated)

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) 2006-2015 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
elessair 0:f269e3021894 19 #include "cmsis.h"
elessair 0:f269e3021894 20 #include "pinmap.h"
elessair 0:f269e3021894 21 #include "clk_freqs.h"
elessair 0:f269e3021894 22 #include "PeripheralPins.h"
elessair 0:f269e3021894 23
elessair 0:f269e3021894 24 static const uint16_t ICR[0x40] = {
elessair 0:f269e3021894 25 20, 22, 24, 26, 28,
elessair 0:f269e3021894 26 30, 34, 40, 28, 32,
elessair 0:f269e3021894 27 36, 40, 44, 48, 56,
elessair 0:f269e3021894 28 68, 48, 56, 64, 72,
elessair 0:f269e3021894 29 80, 88, 104, 128, 80,
elessair 0:f269e3021894 30 96, 112, 128, 144, 160,
elessair 0:f269e3021894 31 192, 240, 160, 192, 224,
elessair 0:f269e3021894 32 256, 288, 320, 384, 480,
elessair 0:f269e3021894 33 320, 384, 448, 512, 576,
elessair 0:f269e3021894 34 640, 768, 960, 640, 768,
elessair 0:f269e3021894 35 896, 1024, 1152, 1280, 1536,
elessair 0:f269e3021894 36 1920, 1280, 1536, 1792, 2048,
elessair 0:f269e3021894 37 2304, 2560, 3072, 3840
elessair 0:f269e3021894 38 };
elessair 0:f269e3021894 39
elessair 0:f269e3021894 40
elessair 0:f269e3021894 41 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
elessair 0:f269e3021894 42 // determine the I2C to use
elessair 0:f269e3021894 43 I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
elessair 0:f269e3021894 44 I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL);
elessair 0:f269e3021894 45 obj->i2c = (I2C_Type*)pinmap_merge(i2c_sda, i2c_scl);
elessair 0:f269e3021894 46 MBED_ASSERT((int)obj->i2c != NC);
elessair 0:f269e3021894 47
elessair 0:f269e3021894 48 #if defined(TARGET_K20DX256)
elessair 0:f269e3021894 49 switch ((int)obj->i2c) {
elessair 0:f269e3021894 50 case I2C_0: SIM->SCGC4 |= SIM_SCGC4_I2C0_MASK;
elessair 0:f269e3021894 51 case I2C_1: SIM->SCGC4 |= SIM_SCGC4_I2C1_MASK;
elessair 0:f269e3021894 52 }
elessair 0:f269e3021894 53 #else
elessair 0:f269e3021894 54 SIM->SCGC4 |= SIM_SCGC4_I2C0_MASK;
elessair 0:f269e3021894 55 #endif
elessair 0:f269e3021894 56
elessair 0:f269e3021894 57 // set default frequency at 100k
elessair 0:f269e3021894 58 i2c_frequency(obj, 100000);
elessair 0:f269e3021894 59
elessair 0:f269e3021894 60 // enable I2C interface
elessair 0:f269e3021894 61 obj->i2c->C1 |= 0x80;
elessair 0:f269e3021894 62
elessair 0:f269e3021894 63 pinmap_pinout(sda, PinMap_I2C_SDA);
elessair 0:f269e3021894 64 pinmap_pinout(scl, PinMap_I2C_SCL);
elessair 0:f269e3021894 65 /* enable open drain for I2C pins, only port b available */
elessair 0:f269e3021894 66 uint32_t pin_n = (uint32_t)(sda & 0x7C) >> 2;
elessair 0:f269e3021894 67 PORTB->PCR[pin_n] |= PORT_PCR_ODE_MASK;
elessair 0:f269e3021894 68 pin_n = (uint32_t)(scl & 0x7C) >> 2;
elessair 0:f269e3021894 69 PORTB->PCR[pin_n] |= PORT_PCR_ODE_MASK;
elessair 0:f269e3021894 70 }
elessair 0:f269e3021894 71
elessair 0:f269e3021894 72 int i2c_start(i2c_t *obj) {
elessair 0:f269e3021894 73 // if we are in the middle of a transaction
elessair 0:f269e3021894 74 // activate the repeat_start flag
elessair 0:f269e3021894 75 if (obj->i2c->S & I2C_S_BUSY_MASK) {
elessair 0:f269e3021894 76 obj->i2c->C1 |= 0x04;
elessair 0:f269e3021894 77 } else {
elessair 0:f269e3021894 78 obj->i2c->C1 |= I2C_C1_MST_MASK;
elessair 0:f269e3021894 79 obj->i2c->C1 |= I2C_C1_TX_MASK;
elessair 0:f269e3021894 80 }
elessair 0:f269e3021894 81 return 0;
elessair 0:f269e3021894 82 }
elessair 0:f269e3021894 83
elessair 0:f269e3021894 84 int i2c_stop(i2c_t *obj) {
elessair 0:f269e3021894 85 volatile uint32_t n = 0;
elessair 0:f269e3021894 86 obj->i2c->C1 &= ~I2C_C1_MST_MASK;
elessair 0:f269e3021894 87 obj->i2c->C1 &= ~I2C_C1_TX_MASK;
elessair 0:f269e3021894 88 while(obj->i2c->S & I2C_S_BUSY_MASK);
elessair 0:f269e3021894 89 return 0;
elessair 0:f269e3021894 90 }
elessair 0:f269e3021894 91
elessair 0:f269e3021894 92 static int timeout_status_poll(i2c_t *obj, uint32_t mask) {
elessair 0:f269e3021894 93 uint32_t i, timeout = 100000;
elessair 0:f269e3021894 94
elessair 0:f269e3021894 95 for (i = 0; i < timeout; i++) {
elessair 0:f269e3021894 96 if (obj->i2c->S & mask)
elessair 0:f269e3021894 97 return 0;
elessair 0:f269e3021894 98 }
elessair 0:f269e3021894 99
elessair 0:f269e3021894 100 return 1;
elessair 0:f269e3021894 101 }
elessair 0:f269e3021894 102
elessair 0:f269e3021894 103 // this function waits the end of a tx transfer and return the status of the transaction:
elessair 0:f269e3021894 104 // 0: OK ack received
elessair 0:f269e3021894 105 // 1: OK ack not received
elessair 0:f269e3021894 106 // 2: failure
elessair 0:f269e3021894 107 static int i2c_wait_end_tx_transfer(i2c_t *obj) {
elessair 0:f269e3021894 108
elessair 0:f269e3021894 109 // wait for the interrupt flag
elessair 0:f269e3021894 110 if (timeout_status_poll(obj, I2C_S_IICIF_MASK)) {
elessair 0:f269e3021894 111 return 2;
elessair 0:f269e3021894 112 }
elessair 0:f269e3021894 113
elessair 0:f269e3021894 114 obj->i2c->S |= I2C_S_IICIF_MASK;
elessair 0:f269e3021894 115
elessair 0:f269e3021894 116 // wait transfer complete
elessair 0:f269e3021894 117 if (timeout_status_poll(obj, I2C_S_TCF_MASK)) {
elessair 0:f269e3021894 118 return 2;
elessair 0:f269e3021894 119 }
elessair 0:f269e3021894 120
elessair 0:f269e3021894 121 // check if we received the ACK or not
elessair 0:f269e3021894 122 return obj->i2c->S & I2C_S_RXAK_MASK ? 1 : 0;
elessair 0:f269e3021894 123 }
elessair 0:f269e3021894 124
elessair 0:f269e3021894 125 // this function waits the end of a rx transfer and return the status of the transaction:
elessair 0:f269e3021894 126 // 0: OK
elessair 0:f269e3021894 127 // 1: failure
elessair 0:f269e3021894 128 static int i2c_wait_end_rx_transfer(i2c_t *obj) {
elessair 0:f269e3021894 129 // wait for the end of the rx transfer
elessair 0:f269e3021894 130 if (timeout_status_poll(obj, I2C_S_IICIF_MASK)) {
elessair 0:f269e3021894 131 return 1;
elessair 0:f269e3021894 132 }
elessair 0:f269e3021894 133
elessair 0:f269e3021894 134 obj->i2c->S |= I2C_S_IICIF_MASK;
elessair 0:f269e3021894 135
elessair 0:f269e3021894 136 return 0;
elessair 0:f269e3021894 137 }
elessair 0:f269e3021894 138
elessair 0:f269e3021894 139 static void i2c_send_nack(i2c_t *obj) {
elessair 0:f269e3021894 140 obj->i2c->C1 |= I2C_C1_TXAK_MASK; // NACK
elessair 0:f269e3021894 141 }
elessair 0:f269e3021894 142
elessair 0:f269e3021894 143 static void i2c_send_ack(i2c_t *obj) {
elessair 0:f269e3021894 144 obj->i2c->C1 &= ~I2C_C1_TXAK_MASK; // ACK
elessair 0:f269e3021894 145 }
elessair 0:f269e3021894 146
elessair 0:f269e3021894 147 static int i2c_do_write(i2c_t *obj, int value) {
elessair 0:f269e3021894 148 // write the data
elessair 0:f269e3021894 149 obj->i2c->D = value;
elessair 0:f269e3021894 150
elessair 0:f269e3021894 151 // init and wait the end of the transfer
elessair 0:f269e3021894 152 return i2c_wait_end_tx_transfer(obj);
elessair 0:f269e3021894 153 }
elessair 0:f269e3021894 154
elessair 0:f269e3021894 155 static int i2c_do_read(i2c_t *obj, char * data, int last) {
elessair 0:f269e3021894 156 if (last) {
elessair 0:f269e3021894 157 i2c_send_nack(obj);
elessair 0:f269e3021894 158 } else {
elessair 0:f269e3021894 159 i2c_send_ack(obj);
elessair 0:f269e3021894 160 }
elessair 0:f269e3021894 161
elessair 0:f269e3021894 162 *data = (obj->i2c->D & 0xFF);
elessair 0:f269e3021894 163
elessair 0:f269e3021894 164 // start rx transfer and wait the end of the transfer
elessair 0:f269e3021894 165 return i2c_wait_end_rx_transfer(obj);
elessair 0:f269e3021894 166 }
elessair 0:f269e3021894 167
elessair 0:f269e3021894 168 void i2c_frequency(i2c_t *obj, int hz) {
elessair 0:f269e3021894 169 uint8_t icr = 0;
elessair 0:f269e3021894 170 uint8_t mult = 0;
elessair 0:f269e3021894 171 uint32_t error = 0;
elessair 0:f269e3021894 172 uint32_t p_error = 0xffffffff;
elessair 0:f269e3021894 173 uint32_t ref = 0;
elessair 0:f269e3021894 174 uint8_t i, j;
elessair 0:f269e3021894 175 // bus clk
elessair 0:f269e3021894 176 uint32_t PCLK = bus_frequency();
elessair 0:f269e3021894 177 uint32_t pulse = PCLK / (hz * 2);
elessair 0:f269e3021894 178
elessair 0:f269e3021894 179 // we look for the values that minimize the error
elessair 0:f269e3021894 180
elessair 0:f269e3021894 181 // test all the MULT values
elessair 0:f269e3021894 182 for (i = 1; i < 5; i*=2) {
elessair 0:f269e3021894 183 for (j = 0; j < 0x40; j++) {
elessair 0:f269e3021894 184 ref = PCLK / (i*ICR[j]);
elessair 0:f269e3021894 185 if (ref > (uint32_t)hz)
elessair 0:f269e3021894 186 continue;
elessair 0:f269e3021894 187 error = hz - ref;
elessair 0:f269e3021894 188 if (error < p_error) {
elessair 0:f269e3021894 189 icr = j;
elessair 0:f269e3021894 190 mult = i/2;
elessair 0:f269e3021894 191 p_error = error;
elessair 0:f269e3021894 192 }
elessair 0:f269e3021894 193 }
elessair 0:f269e3021894 194 }
elessair 0:f269e3021894 195 pulse = icr | (mult << 6);
elessair 0:f269e3021894 196
elessair 0:f269e3021894 197 // I2C Rate
elessair 0:f269e3021894 198 obj->i2c->F = pulse;
elessair 0:f269e3021894 199 }
elessair 0:f269e3021894 200
elessair 0:f269e3021894 201 int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
elessair 0:f269e3021894 202 int count;
elessair 0:f269e3021894 203 char dummy_read, *ptr;
elessair 0:f269e3021894 204
elessair 0:f269e3021894 205 if (i2c_start(obj)) {
elessair 0:f269e3021894 206 i2c_stop(obj);
elessair 0:f269e3021894 207 return I2C_ERROR_BUS_BUSY;
elessair 0:f269e3021894 208 }
elessair 0:f269e3021894 209
elessair 0:f269e3021894 210 if (i2c_do_write(obj, (address | 0x01))) {
elessair 0:f269e3021894 211 i2c_stop(obj);
elessair 0:f269e3021894 212 return I2C_ERROR_NO_SLAVE;
elessair 0:f269e3021894 213 }
elessair 0:f269e3021894 214
elessair 0:f269e3021894 215 // set rx mode
elessair 0:f269e3021894 216 obj->i2c->C1 &= ~I2C_C1_TX_MASK;
elessair 0:f269e3021894 217
elessair 0:f269e3021894 218 // Read in bytes
elessair 0:f269e3021894 219 for (count = 0; count < (length); count++) {
elessair 0:f269e3021894 220 ptr = (count == 0) ? &dummy_read : &data[count - 1];
elessair 0:f269e3021894 221 uint8_t stop_ = (count == (length - 1)) ? 1 : 0;
elessair 0:f269e3021894 222 if (i2c_do_read(obj, ptr, stop_)) {
elessair 0:f269e3021894 223 i2c_stop(obj);
elessair 0:f269e3021894 224 return count;
elessair 0:f269e3021894 225 }
elessair 0:f269e3021894 226 }
elessair 0:f269e3021894 227
elessair 0:f269e3021894 228 // If not repeated start, send stop.
elessair 0:f269e3021894 229 if (stop)
elessair 0:f269e3021894 230 i2c_stop(obj);
elessair 0:f269e3021894 231
elessair 0:f269e3021894 232 // last read
elessair 0:f269e3021894 233 data[count-1] = obj->i2c->D;
elessair 0:f269e3021894 234
elessair 0:f269e3021894 235 return length;
elessair 0:f269e3021894 236 }
elessair 0:f269e3021894 237 int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
elessair 0:f269e3021894 238 int i;
elessair 0:f269e3021894 239
elessair 0:f269e3021894 240 if (i2c_start(obj)) {
elessair 0:f269e3021894 241 i2c_stop(obj);
elessair 0:f269e3021894 242 return I2C_ERROR_BUS_BUSY;
elessair 0:f269e3021894 243 }
elessair 0:f269e3021894 244
elessair 0:f269e3021894 245 if (i2c_do_write(obj, (address & 0xFE))) {
elessair 0:f269e3021894 246 i2c_stop(obj);
elessair 0:f269e3021894 247 return I2C_ERROR_NO_SLAVE;
elessair 0:f269e3021894 248 }
elessair 0:f269e3021894 249
elessair 0:f269e3021894 250 for (i = 0; i < length; i++) {
elessair 0:f269e3021894 251 if(i2c_do_write(obj, data[i])) {
elessair 0:f269e3021894 252 i2c_stop(obj);
elessair 0:f269e3021894 253 return i;
elessair 0:f269e3021894 254 }
elessair 0:f269e3021894 255 }
elessair 0:f269e3021894 256
elessair 0:f269e3021894 257 if (stop)
elessair 0:f269e3021894 258 i2c_stop(obj);
elessair 0:f269e3021894 259
elessair 0:f269e3021894 260 return length;
elessair 0:f269e3021894 261 }
elessair 0:f269e3021894 262
elessair 0:f269e3021894 263 void i2c_reset(i2c_t *obj) {
elessair 0:f269e3021894 264 i2c_stop(obj);
elessair 0:f269e3021894 265 }
elessair 0:f269e3021894 266
elessair 0:f269e3021894 267 int i2c_byte_read(i2c_t *obj, int last) {
elessair 0:f269e3021894 268 char data;
elessair 0:f269e3021894 269
elessair 0:f269e3021894 270 // set rx mode
elessair 0:f269e3021894 271 obj->i2c->C1 &= ~I2C_C1_TX_MASK;
elessair 0:f269e3021894 272
elessair 0:f269e3021894 273 // Setup read
elessair 0:f269e3021894 274 i2c_do_read(obj, &data, last);
elessair 0:f269e3021894 275
elessair 0:f269e3021894 276 // set tx mode
elessair 0:f269e3021894 277 obj->i2c->C1 |= I2C_C1_TX_MASK;
elessair 0:f269e3021894 278 return obj->i2c->D;
elessair 0:f269e3021894 279 }
elessair 0:f269e3021894 280
elessair 0:f269e3021894 281 int i2c_byte_write(i2c_t *obj, int data) {
elessair 0:f269e3021894 282 // set tx mode
elessair 0:f269e3021894 283 obj->i2c->C1 |= I2C_C1_TX_MASK;
elessair 0:f269e3021894 284
elessair 0:f269e3021894 285 return !i2c_do_write(obj, (data & 0xFF));
elessair 0:f269e3021894 286 }
elessair 0:f269e3021894 287
elessair 0:f269e3021894 288
elessair 0:f269e3021894 289 #if DEVICE_I2CSLAVE
elessair 0:f269e3021894 290 void i2c_slave_mode(i2c_t *obj, int enable_slave) {
elessair 0:f269e3021894 291 if (enable_slave) {
elessair 0:f269e3021894 292 // set slave mode
elessair 0:f269e3021894 293 obj->i2c->C1 &= ~I2C_C1_MST_MASK;
elessair 0:f269e3021894 294 obj->i2c->C1 |= I2C_C1_IICIE_MASK;
elessair 0:f269e3021894 295 } else {
elessair 0:f269e3021894 296 // set master mode
elessair 0:f269e3021894 297 obj->i2c->C1 |= I2C_C1_MST_MASK;
elessair 0:f269e3021894 298 }
elessair 0:f269e3021894 299 }
elessair 0:f269e3021894 300
elessair 0:f269e3021894 301 int i2c_slave_receive(i2c_t *obj) {
elessair 0:f269e3021894 302 switch(obj->i2c->S) {
elessair 0:f269e3021894 303 // read addressed
elessair 0:f269e3021894 304 case 0xE6:
elessair 0:f269e3021894 305 return 1;
elessair 0:f269e3021894 306 // write addressed
elessair 0:f269e3021894 307 case 0xE2:
elessair 0:f269e3021894 308 return 3;
elessair 0:f269e3021894 309 default:
elessair 0:f269e3021894 310 return 0;
elessair 0:f269e3021894 311 }
elessair 0:f269e3021894 312 }
elessair 0:f269e3021894 313
elessair 0:f269e3021894 314 int i2c_slave_read(i2c_t *obj, char *data, int length) {
elessair 0:f269e3021894 315 uint8_t dummy_read;
elessair 0:f269e3021894 316 uint8_t * ptr;
elessair 0:f269e3021894 317 int count;
elessair 0:f269e3021894 318
elessair 0:f269e3021894 319 // set rx mode
elessair 0:f269e3021894 320 obj->i2c->C1 &= ~I2C_C1_TX_MASK;
elessair 0:f269e3021894 321
elessair 0:f269e3021894 322 // first dummy read
elessair 0:f269e3021894 323 dummy_read = obj->i2c->D;
elessair 0:f269e3021894 324 if (i2c_wait_end_rx_transfer(obj))
elessair 0:f269e3021894 325 return 0;
elessair 0:f269e3021894 326
elessair 0:f269e3021894 327 // read address
elessair 0:f269e3021894 328 dummy_read = obj->i2c->D;
elessair 0:f269e3021894 329 if (i2c_wait_end_rx_transfer(obj))
elessair 0:f269e3021894 330 return 0;
elessair 0:f269e3021894 331
elessair 0:f269e3021894 332 // read (length - 1) bytes
elessair 0:f269e3021894 333 for (count = 0; count < (length - 1); count++) {
elessair 0:f269e3021894 334 data[count] = obj->i2c->D;
elessair 0:f269e3021894 335 if (i2c_wait_end_rx_transfer(obj))
elessair 0:f269e3021894 336 return count;
elessair 0:f269e3021894 337 }
elessair 0:f269e3021894 338
elessair 0:f269e3021894 339 // read last byte
elessair 0:f269e3021894 340 ptr = (length == 0) ? &dummy_read : (uint8_t *)&data[count];
elessair 0:f269e3021894 341 *ptr = obj->i2c->D;
elessair 0:f269e3021894 342
elessair 0:f269e3021894 343 return (length) ? (count + 1) : 0;
elessair 0:f269e3021894 344 }
elessair 0:f269e3021894 345
elessair 0:f269e3021894 346 int i2c_slave_write(i2c_t *obj, const char *data, int length) {
elessair 0:f269e3021894 347 int i, count = 0;
elessair 0:f269e3021894 348
elessair 0:f269e3021894 349 // set tx mode
elessair 0:f269e3021894 350 obj->i2c->C1 |= I2C_C1_TX_MASK;
elessair 0:f269e3021894 351
elessair 0:f269e3021894 352 for (i = 0; i < length; i++) {
elessair 0:f269e3021894 353 if (i2c_do_write(obj, data[count++]) == 2)
elessair 0:f269e3021894 354 return i;
elessair 0:f269e3021894 355 }
elessair 0:f269e3021894 356
elessair 0:f269e3021894 357 // set rx mode
elessair 0:f269e3021894 358 obj->i2c->C1 &= ~I2C_C1_TX_MASK;
elessair 0:f269e3021894 359
elessair 0:f269e3021894 360 // dummy rx transfer needed
elessair 0:f269e3021894 361 // otherwise the master cannot generate a stop bit
elessair 0:f269e3021894 362 obj->i2c->D;
elessair 0:f269e3021894 363 if (i2c_wait_end_rx_transfer(obj) == 2)
elessair 0:f269e3021894 364 return count;
elessair 0:f269e3021894 365
elessair 0:f269e3021894 366 return count;
elessair 0:f269e3021894 367 }
elessair 0:f269e3021894 368
elessair 0:f269e3021894 369 void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask) {
elessair 0:f269e3021894 370 obj->i2c->A1 = address & 0xfe;
elessair 0:f269e3021894 371 }
elessair 0:f269e3021894 372 #endif