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The official Mbed 2 C/C++ SDK provides the software platform and libraries to build your applications.

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mbed 2

This is the mbed 2 library. If you'd like to learn about Mbed OS please see the mbed-os docs.

drivers/I2C.h@172:65be27845400, 2019-02-20 (annotated)

Committer:
AnnaBridge
Date:
Wed Feb 20 20:53:29 2019 +0000
Revision:
172:65be27845400
Parent:
171:3a7713b1edbc 
mbed library release version 165

Who changed what in which revision?

UserRevisionLine numberNew contents of line
AnnaBridge 156:ff21514d8981 1 /* mbed Microcontroller Library
AnnaBridge 156:ff21514d8981 2 * Copyright (c) 2006-2015 ARM Limited
AnnaBridge 172:65be27845400 3 * SPDX-License-Identifier: Apache-2.0
AnnaBridge 156:ff21514d8981 4 *
AnnaBridge 156:ff21514d8981 5 * Licensed under the Apache License, Version 2.0 (the "License");
AnnaBridge 156:ff21514d8981 6 * you may not use this file except in compliance with the License.
AnnaBridge 156:ff21514d8981 7 * You may obtain a copy of the License at
AnnaBridge 156:ff21514d8981 8 *
AnnaBridge 156:ff21514d8981 9 * http://www.apache.org/licenses/LICENSE-2.0
AnnaBridge 156:ff21514d8981 10 *
AnnaBridge 156:ff21514d8981 11 * Unless required by applicable law or agreed to in writing, software
AnnaBridge 156:ff21514d8981 12 * distributed under the License is distributed on an "AS IS" BASIS,
AnnaBridge 156:ff21514d8981 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
AnnaBridge 156:ff21514d8981 14 * See the License for the specific language governing permissions and
AnnaBridge 156:ff21514d8981 15 * limitations under the License.
AnnaBridge 156:ff21514d8981 16 */
AnnaBridge 156:ff21514d8981 17 #ifndef MBED_I2C_H
AnnaBridge 156:ff21514d8981 18 #define MBED_I2C_H
AnnaBridge 156:ff21514d8981 19
AnnaBridge 156:ff21514d8981 20 #include "platform/platform.h"
AnnaBridge 172:65be27845400 21 #include "hal/gpio_api.h"
AnnaBridge 156:ff21514d8981 22
AnnaBridge 172:65be27845400 23 #if DEVICE_I2C || defined(DOXYGEN_ONLY)
AnnaBridge 156:ff21514d8981 24
AnnaBridge 156:ff21514d8981 25 #include "hal/i2c_api.h"
AnnaBridge 156:ff21514d8981 26 #include "platform/SingletonPtr.h"
AnnaBridge 156:ff21514d8981 27 #include "platform/PlatformMutex.h"
AnnaBridge 156:ff21514d8981 28 #include "platform/NonCopyable.h"
AnnaBridge 156:ff21514d8981 29
AnnaBridge 156:ff21514d8981 30 #if DEVICE_I2C_ASYNCH
AnnaBridge 156:ff21514d8981 31 #include "platform/CThunk.h"
AnnaBridge 156:ff21514d8981 32 #include "hal/dma_api.h"
AnnaBridge 156:ff21514d8981 33 #include "platform/FunctionPointer.h"
AnnaBridge 156:ff21514d8981 34 #endif
AnnaBridge 156:ff21514d8981 35
AnnaBridge 156:ff21514d8981 36 namespace mbed {
AnnaBridge 156:ff21514d8981 37 /** \addtogroup drivers */
AnnaBridge 156:ff21514d8981 38
AnnaBridge 156:ff21514d8981 39 /** An I2C Master, used for communicating with I2C slave devices
AnnaBridge 156:ff21514d8981 40 *
AnnaBridge 156:ff21514d8981 41 * @note Synchronization level: Thread safe
AnnaBridge 156:ff21514d8981 42 *
AnnaBridge 156:ff21514d8981 43 * Example:
AnnaBridge 156:ff21514d8981 44 * @code
AnnaBridge 172:65be27845400 45 * Read temperature from LM75BD
AnnaBridge 156:ff21514d8981 46 * #include "mbed.h"
AnnaBridge 172:65be27845400 47 * I2C i2c(I2C_SDA , I2C_SCL);
AnnaBridge 172:65be27845400 48 * const int addr7bit = 0x48; // 7-bit I2C address
AnnaBridge 172:65be27845400 49 * const int addr8bit = 0x48 << 1; // 8-bit I2C address, 0x90
AnnaBridge 156:ff21514d8981 50 *
AnnaBridge 156:ff21514d8981 51 * int main() {
AnnaBridge 172:65be27845400 52 * char cmd[2];
AnnaBridge 172:65be27845400 53 * while (1) {
AnnaBridge 172:65be27845400 54 * cmd[0] = 0x01;
AnnaBridge 172:65be27845400 55 * cmd[1] = 0x00;
AnnaBridge 172:65be27845400 56 *
AnnaBridge 172:65be27845400 57 * // read and write takes the 8-bit version of the address.
AnnaBridge 172:65be27845400 58 * // set up configuration register (at 0x01)
AnnaBridge 172:65be27845400 59 * i2c.write(addr8bit, cmd, 2);
AnnaBridge 172:65be27845400 60 *
AnnaBridge 172:65be27845400 61 * wait(0.5);
AnnaBridge 172:65be27845400 62 *
AnnaBridge 172:65be27845400 63 * // read temperature register
AnnaBridge 172:65be27845400 64 * cmd[0] = 0x00;
AnnaBridge 172:65be27845400 65 * i2c.write(addr8bit, cmd, 1);
AnnaBridge 172:65be27845400 66 * i2c.read( addr8bit, cmd, 2);
AnnaBridge 172:65be27845400 67 *
AnnaBridge 172:65be27845400 68 * float tmp = (float((cmd[0]<<8)|cmd[1]) / 256.0);
AnnaBridge 172:65be27845400 69 * printf("Temp = %.2f\n", tmp);
AnnaBridge 172:65be27845400 70 * }
AnnaBridge 156:ff21514d8981 71 * }
AnnaBridge 156:ff21514d8981 72 * @endcode
AnnaBridge 156:ff21514d8981 73 * @ingroup drivers
AnnaBridge 156:ff21514d8981 74 */
AnnaBridge 156:ff21514d8981 75 class I2C : private NonCopyable<I2C> {
AnnaBridge 156:ff21514d8981 76
AnnaBridge 156:ff21514d8981 77 public:
AnnaBridge 156:ff21514d8981 78 enum RxStatus {
AnnaBridge 156:ff21514d8981 79 NoData,
AnnaBridge 156:ff21514d8981 80 MasterGeneralCall,
AnnaBridge 156:ff21514d8981 81 MasterWrite,
AnnaBridge 156:ff21514d8981 82 MasterRead
AnnaBridge 156:ff21514d8981 83 };
AnnaBridge 156:ff21514d8981 84
AnnaBridge 156:ff21514d8981 85 enum Acknowledge {
AnnaBridge 156:ff21514d8981 86 NoACK = 0,
AnnaBridge 156:ff21514d8981 87 ACK = 1
AnnaBridge 156:ff21514d8981 88 };
AnnaBridge 156:ff21514d8981 89
AnnaBridge 156:ff21514d8981 90 /** Create an I2C Master interface, connected to the specified pins
AnnaBridge 156:ff21514d8981 91 *
AnnaBridge 156:ff21514d8981 92 * @param sda I2C data line pin
AnnaBridge 156:ff21514d8981 93 * @param scl I2C clock line pin
AnnaBridge 156:ff21514d8981 94 */
AnnaBridge 156:ff21514d8981 95 I2C(PinName sda, PinName scl);
AnnaBridge 156:ff21514d8981 96
AnnaBridge 156:ff21514d8981 97 /** Set the frequency of the I2C interface
AnnaBridge 156:ff21514d8981 98 *
AnnaBridge 156:ff21514d8981 99 * @param hz The bus frequency in hertz
AnnaBridge 156:ff21514d8981 100 */
AnnaBridge 156:ff21514d8981 101 void frequency(int hz);
AnnaBridge 156:ff21514d8981 102
AnnaBridge 156:ff21514d8981 103 /** Read from an I2C slave
AnnaBridge 156:ff21514d8981 104 *
AnnaBridge 156:ff21514d8981 105 * Performs a complete read transaction. The bottom bit of
AnnaBridge 156:ff21514d8981 106 * the address is forced to 1 to indicate a read.
AnnaBridge 156:ff21514d8981 107 *
AnnaBridge 156:ff21514d8981 108 * @param address 8-bit I2C slave address [ addr | 1 ]
AnnaBridge 156:ff21514d8981 109 * @param data Pointer to the byte-array to read data in to
AnnaBridge 156:ff21514d8981 110 * @param length Number of bytes to read
AnnaBridge 156:ff21514d8981 111 * @param repeated Repeated start, true - don't send stop at end
AnnaBridge 172:65be27845400 112 * default value is false.
AnnaBridge 156:ff21514d8981 113 *
AnnaBridge 156:ff21514d8981 114 * @returns
AnnaBridge 156:ff21514d8981 115 * 0 on success (ack),
AnnaBridge 172:65be27845400 116 * nonzero on failure (nack)
AnnaBridge 156:ff21514d8981 117 */
AnnaBridge 156:ff21514d8981 118 int read(int address, char *data, int length, bool repeated = false);
AnnaBridge 156:ff21514d8981 119
AnnaBridge 156:ff21514d8981 120 /** Read a single byte from the I2C bus
AnnaBridge 156:ff21514d8981 121 *
AnnaBridge 156:ff21514d8981 122 * @param ack indicates if the byte is to be acknowledged (1 = acknowledge)
AnnaBridge 156:ff21514d8981 123 *
AnnaBridge 156:ff21514d8981 124 * @returns
AnnaBridge 156:ff21514d8981 125 * the byte read
AnnaBridge 156:ff21514d8981 126 */
AnnaBridge 156:ff21514d8981 127 int read(int ack);
AnnaBridge 156:ff21514d8981 128
AnnaBridge 156:ff21514d8981 129 /** Write to an I2C slave
AnnaBridge 156:ff21514d8981 130 *
AnnaBridge 156:ff21514d8981 131 * Performs a complete write transaction. The bottom bit of
AnnaBridge 156:ff21514d8981 132 * the address is forced to 0 to indicate a write.
AnnaBridge 156:ff21514d8981 133 *
AnnaBridge 156:ff21514d8981 134 * @param address 8-bit I2C slave address [ addr | 0 ]
AnnaBridge 156:ff21514d8981 135 * @param data Pointer to the byte-array data to send
AnnaBridge 156:ff21514d8981 136 * @param length Number of bytes to send
AnnaBridge 156:ff21514d8981 137 * @param repeated Repeated start, true - do not send stop at end
AnnaBridge 172:65be27845400 138 * default value is false.
AnnaBridge 156:ff21514d8981 139 *
AnnaBridge 156:ff21514d8981 140 * @returns
AnnaBridge 156:ff21514d8981 141 * 0 on success (ack),
AnnaBridge 172:65be27845400 142 * nonzero on failure (nack)
AnnaBridge 156:ff21514d8981 143 */
AnnaBridge 156:ff21514d8981 144 int write(int address, const char *data, int length, bool repeated = false);
AnnaBridge 156:ff21514d8981 145
AnnaBridge 156:ff21514d8981 146 /** Write single byte out on the I2C bus
AnnaBridge 156:ff21514d8981 147 *
AnnaBridge 156:ff21514d8981 148 * @param data data to write out on bus
AnnaBridge 156:ff21514d8981 149 *
AnnaBridge 156:ff21514d8981 150 * @returns
AnnaBridge 156:ff21514d8981 151 * '0' - NAK was received
AnnaBridge 156:ff21514d8981 152 * '1' - ACK was received,
AnnaBridge 156:ff21514d8981 153 * '2' - timeout
AnnaBridge 156:ff21514d8981 154 */
AnnaBridge 156:ff21514d8981 155 int write(int data);
AnnaBridge 156:ff21514d8981 156
AnnaBridge 156:ff21514d8981 157 /** Creates a start condition on the I2C bus
AnnaBridge 156:ff21514d8981 158 */
AnnaBridge 156:ff21514d8981 159 void start(void);
AnnaBridge 156:ff21514d8981 160
AnnaBridge 156:ff21514d8981 161 /** Creates a stop condition on the I2C bus
AnnaBridge 156:ff21514d8981 162 */
AnnaBridge 156:ff21514d8981 163 void stop(void);
AnnaBridge 156:ff21514d8981 164
AnnaBridge 156:ff21514d8981 165 /** Acquire exclusive access to this I2C bus
AnnaBridge 156:ff21514d8981 166 */
AnnaBridge 156:ff21514d8981 167 virtual void lock(void);
AnnaBridge 156:ff21514d8981 168
AnnaBridge 156:ff21514d8981 169 /** Release exclusive access to this I2C bus
AnnaBridge 156:ff21514d8981 170 */
AnnaBridge 156:ff21514d8981 171 virtual void unlock(void);
AnnaBridge 156:ff21514d8981 172
AnnaBridge 170:e95d10626187 173 virtual ~I2C()
AnnaBridge 170:e95d10626187 174 {
AnnaBridge 156:ff21514d8981 175 // Do nothing
AnnaBridge 156:ff21514d8981 176 }
AnnaBridge 156:ff21514d8981 177
AnnaBridge 156:ff21514d8981 178 #if DEVICE_I2C_ASYNCH
AnnaBridge 156:ff21514d8981 179
AnnaBridge 172:65be27845400 180 /** Start nonblocking I2C transfer.
AnnaBridge 156:ff21514d8981 181 *
AnnaBridge 165:d1b4690b3f8b 182 * This function locks the deep sleep until any event has occurred
AnnaBridge 170:e95d10626187 183 *
AnnaBridge 165:d1b4690b3f8b 184 * @param address 8/10 bit I2C slave address
AnnaBridge 171:3a7713b1edbc 185 * @param tx_buffer The TX buffer with data to be transferred
AnnaBridge 156:ff21514d8981 186 * @param tx_length The length of TX buffer in bytes
AnnaBridge 172:65be27845400 187 * @param rx_buffer The RX buffer, which is used for received data
AnnaBridge 156:ff21514d8981 188 * @param rx_length The length of RX buffer in bytes
AnnaBridge 156:ff21514d8981 189 * @param event The logical OR of events to modify
AnnaBridge 156:ff21514d8981 190 * @param callback The event callback function
AnnaBridge 156:ff21514d8981 191 * @param repeated Repeated start, true - do not send stop at end
AnnaBridge 172:65be27845400 192 * default value is false.
AnnaBridge 172:65be27845400 193 *
AnnaBridge 172:65be27845400 194 * @returns Zero if the transfer has started, or -1 if I2C peripheral is busy
AnnaBridge 156:ff21514d8981 195 */
AnnaBridge 170:e95d10626187 196 int transfer(int address, const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length, const event_callback_t &callback, int event = I2C_EVENT_TRANSFER_COMPLETE, bool repeated = false);
AnnaBridge 156:ff21514d8981 197
AnnaBridge 172:65be27845400 198 /** Abort the ongoing I2C transfer
AnnaBridge 156:ff21514d8981 199 */
AnnaBridge 156:ff21514d8981 200 void abort_transfer();
Anna Bridge 160:5571c4ff569f 201
AnnaBridge 172:65be27845400 202 #if !defined(DOXYGEN_ONLY)
AnnaBridge 170:e95d10626187 203 protected:
Anna Bridge 160:5571c4ff569f 204 /** Lock deep sleep only if it is not yet locked */
Anna Bridge 160:5571c4ff569f 205 void lock_deep_sleep();
Anna Bridge 160:5571c4ff569f 206
Anna Bridge 160:5571c4ff569f 207 /** Unlock deep sleep only if it has been locked */
Anna Bridge 160:5571c4ff569f 208 void unlock_deep_sleep();
Anna Bridge 160:5571c4ff569f 209
AnnaBridge 156:ff21514d8981 210 void irq_handler_asynch(void);
AnnaBridge 156:ff21514d8981 211 event_callback_t _callback;
AnnaBridge 156:ff21514d8981 212 CThunk<I2C> _irq;
AnnaBridge 156:ff21514d8981 213 DMAUsage _usage;
Anna Bridge 160:5571c4ff569f 214 bool _deep_sleep_locked;
AnnaBridge 156:ff21514d8981 215 #endif
AnnaBridge 172:65be27845400 216 #endif
AnnaBridge 156:ff21514d8981 217
AnnaBridge 172:65be27845400 218 #if !defined(DOXYGEN_ONLY)
AnnaBridge 156:ff21514d8981 219 protected:
AnnaBridge 156:ff21514d8981 220 void aquire();
AnnaBridge 156:ff21514d8981 221
AnnaBridge 156:ff21514d8981 222 i2c_t _i2c;
AnnaBridge 156:ff21514d8981 223 static I2C *_owner;
AnnaBridge 172:65be27845400 224 int _hz;
AnnaBridge 156:ff21514d8981 225 static SingletonPtr<PlatformMutex> _mutex;
AnnaBridge 172:65be27845400 226 PinName _sda;
AnnaBridge 172:65be27845400 227 PinName _scl;
AnnaBridge 172:65be27845400 228
AnnaBridge 172:65be27845400 229 private:
AnnaBridge 172:65be27845400 230 /** Recover I2C bus, when stuck with SDA low
AnnaBridge 172:65be27845400 231 * @note : Initialization of I2C bus is required after this API.
AnnaBridge 172:65be27845400 232 *
AnnaBridge 172:65be27845400 233 * @param sda I2C data line pin
AnnaBridge 172:65be27845400 234 * @param scl I2C clock line pin
AnnaBridge 172:65be27845400 235 *
AnnaBridge 172:65be27845400 236 * @returns
AnnaBridge 172:65be27845400 237 * '0' - Successfully recovered
AnnaBridge 172:65be27845400 238 * 'I2C_ERROR_BUS_BUSY' - In case of failure
AnnaBridge 172:65be27845400 239 *
AnnaBridge 172:65be27845400 240 */
AnnaBridge 172:65be27845400 241 int recover(PinName sda, PinName scl);
AnnaBridge 172:65be27845400 242 #endif
AnnaBridge 156:ff21514d8981 243 };
AnnaBridge 156:ff21514d8981 244
AnnaBridge 156:ff21514d8981 245 } // namespace mbed
AnnaBridge 156:ff21514d8981 246
AnnaBridge 156:ff21514d8981 247 #endif
AnnaBridge 156:ff21514d8981 248
AnnaBridge 156:ff21514d8981 249 #endif