mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

Dependents:   Nucleo_Hello_Encoder BLE_iBeaconScan AM1805_DEMO DISCO-F429ZI_ExportTemplate1 ... more

drivers/I2C.cpp@189:f392fc9709a3, 2019-02-20 (annotated)

Committer:
AnnaBridge
Date:
Wed Feb 20 22:31:08 2019 +0000
Revision:
189:f392fc9709a3
Parent:
187:0387e8f68319 
mbed library release version 165

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 149:156823d33999 1 /* mbed Microcontroller Library
<> 149:156823d33999 2 * Copyright (c) 2006-2015 ARM Limited
AnnaBridge 189:f392fc9709a3 3 * SPDX-License-Identifier: Apache-2.0
<> 149:156823d33999 4 *
<> 149:156823d33999 5 * Licensed under the Apache License, Version 2.0 (the "License");
<> 149:156823d33999 6 * you may not use this file except in compliance with the License.
<> 149:156823d33999 7 * You may obtain a copy of the License at
<> 149:156823d33999 8 *
<> 149:156823d33999 9 * http://www.apache.org/licenses/LICENSE-2.0
<> 149:156823d33999 10 *
<> 149:156823d33999 11 * Unless required by applicable law or agreed to in writing, software
<> 149:156823d33999 12 * distributed under the License is distributed on an "AS IS" BASIS,
<> 149:156823d33999 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 149:156823d33999 14 * See the License for the specific language governing permissions and
<> 149:156823d33999 15 * limitations under the License.
<> 149:156823d33999 16 */
AnnaBridge 189:f392fc9709a3 17
<> 149:156823d33999 18 #include "drivers/I2C.h"
AnnaBridge 189:f392fc9709a3 19 #include "drivers/DigitalInOut.h"
AnnaBridge 189:f392fc9709a3 20 #include "platform/mbed_wait_api.h"
<> 149:156823d33999 21
<> 149:156823d33999 22 #if DEVICE_I2C
<> 149:156823d33999 23
AnnaBridge 174:b96e65c34a4d 24 #if DEVICE_I2C_ASYNCH
AnnaBridge 184:08ed48f1de7f 25 #include "platform/mbed_power_mgmt.h"
AnnaBridge 174:b96e65c34a4d 26 #endif
AnnaBridge 174:b96e65c34a4d 27
<> 149:156823d33999 28 namespace mbed {
<> 149:156823d33999 29
<> 149:156823d33999 30 I2C *I2C::_owner = NULL;
<> 149:156823d33999 31 SingletonPtr<PlatformMutex> I2C::_mutex;
<> 149:156823d33999 32
<> 149:156823d33999 33 I2C::I2C(PinName sda, PinName scl) :
<> 149:156823d33999 34 #if DEVICE_I2C_ASYNCH
Anna Bridge 180:96ed750bd169 35 _irq(this), _usage(DMA_USAGE_NEVER), _deep_sleep_locked(false),
<> 149:156823d33999 36 #endif
Anna Bridge 180:96ed750bd169 37 _i2c(), _hz(100000)
Anna Bridge 180:96ed750bd169 38 {
AnnaBridge 189:f392fc9709a3 39 lock();
<> 149:156823d33999 40 // The init function also set the frequency to 100000
AnnaBridge 189:f392fc9709a3 41 _sda = sda;
AnnaBridge 189:f392fc9709a3 42 _scl = scl;
AnnaBridge 189:f392fc9709a3 43 recover(sda, scl);
AnnaBridge 189:f392fc9709a3 44 i2c_init(&_i2c, _sda, _scl);
<> 149:156823d33999 45 // Used to avoid unnecessary frequency updates
<> 149:156823d33999 46 _owner = this;
AnnaBridge 189:f392fc9709a3 47 unlock();
<> 149:156823d33999 48 }
<> 149:156823d33999 49
AnnaBridge 187:0387e8f68319 50 void I2C::frequency(int hz)
AnnaBridge 187:0387e8f68319 51 {
<> 149:156823d33999 52 lock();
<> 149:156823d33999 53 _hz = hz;
<> 149:156823d33999 54
<> 149:156823d33999 55 // We want to update the frequency even if we are already the bus owners
<> 149:156823d33999 56 i2c_frequency(&_i2c, _hz);
<> 149:156823d33999 57
<> 149:156823d33999 58 // Updating the frequency of the bus we become the owners of it
<> 149:156823d33999 59 _owner = this;
<> 149:156823d33999 60 unlock();
<> 149:156823d33999 61 }
<> 149:156823d33999 62
AnnaBridge 187:0387e8f68319 63 void I2C::aquire()
AnnaBridge 187:0387e8f68319 64 {
<> 149:156823d33999 65 lock();
<> 149:156823d33999 66 if (_owner != this) {
<> 149:156823d33999 67 i2c_frequency(&_i2c, _hz);
<> 149:156823d33999 68 _owner = this;
<> 149:156823d33999 69 }
<> 149:156823d33999 70 unlock();
<> 149:156823d33999 71 }
<> 149:156823d33999 72
<> 149:156823d33999 73 // write - Master Transmitter Mode
AnnaBridge 187:0387e8f68319 74 int I2C::write(int address, const char *data, int length, bool repeated)
AnnaBridge 187:0387e8f68319 75 {
<> 149:156823d33999 76 lock();
<> 149:156823d33999 77 aquire();
<> 149:156823d33999 78
<> 149:156823d33999 79 int stop = (repeated) ? 0 : 1;
<> 149:156823d33999 80 int written = i2c_write(&_i2c, address, data, length, stop);
<> 149:156823d33999 81
<> 149:156823d33999 82 unlock();
<> 149:156823d33999 83 return length != written;
<> 149:156823d33999 84 }
<> 149:156823d33999 85
AnnaBridge 187:0387e8f68319 86 int I2C::write(int data)
AnnaBridge 187:0387e8f68319 87 {
<> 149:156823d33999 88 lock();
<> 149:156823d33999 89 int ret = i2c_byte_write(&_i2c, data);
<> 149:156823d33999 90 unlock();
<> 149:156823d33999 91 return ret;
<> 149:156823d33999 92 }
<> 149:156823d33999 93
AnnaBridge 184:08ed48f1de7f 94 // read - Master Receiver Mode
AnnaBridge 187:0387e8f68319 95 int I2C::read(int address, char *data, int length, bool repeated)
AnnaBridge 187:0387e8f68319 96 {
<> 149:156823d33999 97 lock();
<> 149:156823d33999 98 aquire();
<> 149:156823d33999 99
<> 149:156823d33999 100 int stop = (repeated) ? 0 : 1;
<> 149:156823d33999 101 int read = i2c_read(&_i2c, address, data, length, stop);
<> 149:156823d33999 102
<> 149:156823d33999 103 unlock();
<> 149:156823d33999 104 return length != read;
<> 149:156823d33999 105 }
<> 149:156823d33999 106
AnnaBridge 187:0387e8f68319 107 int I2C::read(int ack)
AnnaBridge 187:0387e8f68319 108 {
<> 149:156823d33999 109 lock();
<> 149:156823d33999 110 int ret;
<> 149:156823d33999 111 if (ack) {
<> 149:156823d33999 112 ret = i2c_byte_read(&_i2c, 0);
<> 149:156823d33999 113 } else {
<> 149:156823d33999 114 ret = i2c_byte_read(&_i2c, 1);
<> 149:156823d33999 115 }
<> 149:156823d33999 116 unlock();
<> 149:156823d33999 117 return ret;
<> 149:156823d33999 118 }
<> 149:156823d33999 119
AnnaBridge 187:0387e8f68319 120 void I2C::start(void)
AnnaBridge 187:0387e8f68319 121 {
<> 149:156823d33999 122 lock();
<> 149:156823d33999 123 i2c_start(&_i2c);
<> 149:156823d33999 124 unlock();
<> 149:156823d33999 125 }
<> 149:156823d33999 126
AnnaBridge 187:0387e8f68319 127 void I2C::stop(void)
AnnaBridge 187:0387e8f68319 128 {
<> 149:156823d33999 129 lock();
<> 149:156823d33999 130 i2c_stop(&_i2c);
<> 149:156823d33999 131 unlock();
<> 149:156823d33999 132 }
<> 149:156823d33999 133
AnnaBridge 187:0387e8f68319 134 void I2C::lock()
AnnaBridge 187:0387e8f68319 135 {
<> 149:156823d33999 136 _mutex->lock();
<> 149:156823d33999 137 }
<> 149:156823d33999 138
AnnaBridge 187:0387e8f68319 139 void I2C::unlock()
AnnaBridge 187:0387e8f68319 140 {
<> 149:156823d33999 141 _mutex->unlock();
<> 149:156823d33999 142 }
<> 149:156823d33999 143
AnnaBridge 189:f392fc9709a3 144 int I2C::recover(PinName sda, PinName scl)
AnnaBridge 189:f392fc9709a3 145 {
AnnaBridge 189:f392fc9709a3 146 DigitalInOut pin_sda(sda, PIN_INPUT, PullNone, 1);
AnnaBridge 189:f392fc9709a3 147 DigitalInOut pin_scl(scl, PIN_INPUT, PullNone, 1);
AnnaBridge 189:f392fc9709a3 148
AnnaBridge 189:f392fc9709a3 149 // Return as SCL is low and no access to become master.
AnnaBridge 189:f392fc9709a3 150 if (pin_scl == 0) {
AnnaBridge 189:f392fc9709a3 151 return I2C_ERROR_BUS_BUSY;
AnnaBridge 189:f392fc9709a3 152 }
AnnaBridge 189:f392fc9709a3 153
AnnaBridge 189:f392fc9709a3 154 // Return successfully as SDA and SCL is high
AnnaBridge 189:f392fc9709a3 155 if (pin_sda == 1) {
AnnaBridge 189:f392fc9709a3 156 return 0;
AnnaBridge 189:f392fc9709a3 157 }
AnnaBridge 189:f392fc9709a3 158
AnnaBridge 189:f392fc9709a3 159 // Send clock pulses, for device to recover 9
AnnaBridge 189:f392fc9709a3 160 pin_scl.mode(PullNone);
AnnaBridge 189:f392fc9709a3 161 pin_scl.output();
AnnaBridge 189:f392fc9709a3 162 for (int count = 0; count < 10; count++) {
AnnaBridge 189:f392fc9709a3 163 pin_scl.mode(PullNone);
AnnaBridge 189:f392fc9709a3 164 pin_scl = 0;
AnnaBridge 189:f392fc9709a3 165 wait_us(5);
AnnaBridge 189:f392fc9709a3 166 pin_scl.mode(PullUp);
AnnaBridge 189:f392fc9709a3 167 pin_scl = 1;
AnnaBridge 189:f392fc9709a3 168 wait_us(5);
AnnaBridge 189:f392fc9709a3 169 }
AnnaBridge 189:f392fc9709a3 170
AnnaBridge 189:f392fc9709a3 171 // Send Stop
AnnaBridge 189:f392fc9709a3 172 pin_sda.output();
AnnaBridge 189:f392fc9709a3 173 pin_sda = 0;
AnnaBridge 189:f392fc9709a3 174 wait_us(5);
AnnaBridge 189:f392fc9709a3 175 pin_scl = 1;
AnnaBridge 189:f392fc9709a3 176 wait_us(5);
AnnaBridge 189:f392fc9709a3 177 pin_sda = 1;
AnnaBridge 189:f392fc9709a3 178 wait_us(5);
AnnaBridge 189:f392fc9709a3 179
AnnaBridge 189:f392fc9709a3 180 pin_sda.input();
AnnaBridge 189:f392fc9709a3 181 pin_scl.input();
AnnaBridge 189:f392fc9709a3 182 if ((pin_scl == 0) || (pin_sda == 0)) {
AnnaBridge 189:f392fc9709a3 183 // Return as SCL is low and no access to become master.
AnnaBridge 189:f392fc9709a3 184 return I2C_ERROR_BUS_BUSY;
AnnaBridge 189:f392fc9709a3 185 }
AnnaBridge 189:f392fc9709a3 186
AnnaBridge 189:f392fc9709a3 187 return 0;
AnnaBridge 189:f392fc9709a3 188 }
AnnaBridge 189:f392fc9709a3 189
<> 149:156823d33999 190 #if DEVICE_I2C_ASYNCH
<> 149:156823d33999 191
AnnaBridge 187:0387e8f68319 192 int I2C::transfer(int address, const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length, const event_callback_t &callback, int event, bool repeated)
<> 149:156823d33999 193 {
<> 149:156823d33999 194 lock();
<> 149:156823d33999 195 if (i2c_active(&_i2c)) {
<> 149:156823d33999 196 unlock();
<> 149:156823d33999 197 return -1; // transaction ongoing
<> 149:156823d33999 198 }
Anna Bridge 180:96ed750bd169 199 lock_deep_sleep();
<> 149:156823d33999 200 aquire();
<> 149:156823d33999 201
<> 149:156823d33999 202 _callback = callback;
<> 149:156823d33999 203 int stop = (repeated) ? 0 : 1;
<> 149:156823d33999 204 _irq.callback(&I2C::irq_handler_asynch);
<> 149:156823d33999 205 i2c_transfer_asynch(&_i2c, (void *)tx_buffer, tx_length, (void *)rx_buffer, rx_length, address, stop, _irq.entry(), event, _usage);
<> 149:156823d33999 206 unlock();
<> 149:156823d33999 207 return 0;
<> 149:156823d33999 208 }
<> 149:156823d33999 209
<> 149:156823d33999 210 void I2C::abort_transfer(void)
<> 149:156823d33999 211 {
<> 149:156823d33999 212 lock();
<> 149:156823d33999 213 i2c_abort_asynch(&_i2c);
Anna Bridge 180:96ed750bd169 214 unlock_deep_sleep();
<> 149:156823d33999 215 unlock();
<> 149:156823d33999 216 }
<> 149:156823d33999 217
<> 149:156823d33999 218 void I2C::irq_handler_asynch(void)
<> 149:156823d33999 219 {
<> 149:156823d33999 220 int event = i2c_irq_handler_asynch(&_i2c);
<> 149:156823d33999 221 if (_callback && event) {
<> 149:156823d33999 222 _callback.call(event);
<> 149:156823d33999 223 }
AnnaBridge 189:f392fc9709a3 224
AnnaBridge 174:b96e65c34a4d 225 if (event) {
Anna Bridge 180:96ed750bd169 226 unlock_deep_sleep();
AnnaBridge 174:b96e65c34a4d 227 }
<> 149:156823d33999 228 }
<> 149:156823d33999 229
Anna Bridge 180:96ed750bd169 230 void I2C::lock_deep_sleep()
Anna Bridge 180:96ed750bd169 231 {
Anna Bridge 180:96ed750bd169 232 if (_deep_sleep_locked == false) {
Anna Bridge 180:96ed750bd169 233 sleep_manager_lock_deep_sleep();
Anna Bridge 180:96ed750bd169 234 _deep_sleep_locked = true;
Anna Bridge 180:96ed750bd169 235 }
Anna Bridge 180:96ed750bd169 236 }
Anna Bridge 180:96ed750bd169 237
Anna Bridge 180:96ed750bd169 238 void I2C::unlock_deep_sleep()
Anna Bridge 180:96ed750bd169 239 {
Anna Bridge 180:96ed750bd169 240 if (_deep_sleep_locked == true) {
Anna Bridge 180:96ed750bd169 241 sleep_manager_unlock_deep_sleep();
Anna Bridge 180:96ed750bd169 242 _deep_sleep_locked = false;
Anna Bridge 180:96ed750bd169 243 }
Anna Bridge 180:96ed750bd169 244 }
<> 149:156823d33999 245
<> 149:156823d33999 246 #endif
<> 149:156823d33999 247
<> 149:156823d33999 248 } // namespace mbed
<> 149:156823d33999 249
<> 149:156823d33999 250 #endif