mbed library sources. Supersedes mbed-src.
Dependents: LPCXpresso1769_blinky
Fork of mbed-dev by
I2C.h
00001 /* mbed Microcontroller Library 00002 * Copyright (c) 2006-2015 ARM Limited 00003 * 00004 * Licensed under the Apache License, Version 2.0 (the "License"); 00005 * you may not use this file except in compliance with the License. 00006 * You may obtain a copy of the License at 00007 * 00008 * http://www.apache.org/licenses/LICENSE-2.0 00009 * 00010 * Unless required by applicable law or agreed to in writing, software 00011 * distributed under the License is distributed on an "AS IS" BASIS, 00012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 00013 * See the License for the specific language governing permissions and 00014 * limitations under the License. 00015 */ 00016 #ifndef MBED_I2C_H 00017 #define MBED_I2C_H 00018 00019 #include "platform.h" 00020 00021 #if DEVICE_I2C 00022 00023 #include "i2c_api.h" 00024 #include "SingletonPtr.h" 00025 #include "PlatformMutex.h" 00026 00027 #if DEVICE_I2C_ASYNCH 00028 #include "CThunk.h" 00029 #include "dma_api.h" 00030 #include "FunctionPointer.h" 00031 #endif 00032 00033 namespace mbed { 00034 00035 /** An I2C Master, used for communicating with I2C slave devices 00036 * 00037 * @Note Synchronization level: Thread safe 00038 * 00039 * Example: 00040 * @code 00041 * // Read from I2C slave at address 0x62 00042 * 00043 * #include "mbed.h" 00044 * 00045 * I2C i2c(p28, p27); 00046 * 00047 * int main() { 00048 * int address = 0x62; 00049 * char data[2]; 00050 * i2c.read(address, data, 2); 00051 * } 00052 * @endcode 00053 */ 00054 class I2C { 00055 00056 public: 00057 enum RxStatus { 00058 NoData, 00059 MasterGeneralCall, 00060 MasterWrite, 00061 MasterRead 00062 }; 00063 00064 enum Acknowledge { 00065 NoACK = 0, 00066 ACK = 1 00067 }; 00068 00069 /** Create an I2C Master interface, connected to the specified pins 00070 * 00071 * @param sda I2C data line pin 00072 * @param scl I2C clock line pin 00073 */ 00074 I2C(PinName sda, PinName scl); 00075 00076 /** Set the frequency of the I2C interface 00077 * 00078 * @param hz The bus frequency in hertz 00079 */ 00080 void frequency(int hz); 00081 00082 /** Read from an I2C slave 00083 * 00084 * Performs a complete read transaction. The bottom bit of 00085 * the address is forced to 1 to indicate a read. 00086 * 00087 * @param address 8-bit I2C slave address [ addr | 1 ] 00088 * @param data Pointer to the byte-array to read data in to 00089 * @param length Number of bytes to read 00090 * @param repeated Repeated start, true - don't send stop at end 00091 * 00092 * @returns 00093 * 0 on success (ack), 00094 * non-0 on failure (nack) 00095 */ 00096 int read(int address, char *data, int length, bool repeated = false); 00097 00098 /** Read a single byte from the I2C bus 00099 * 00100 * @param ack indicates if the byte is to be acknowledged (1 = acknowledge) 00101 * 00102 * @returns 00103 * the byte read 00104 */ 00105 int read(int ack); 00106 00107 /** Write to an I2C slave 00108 * 00109 * Performs a complete write transaction. The bottom bit of 00110 * the address is forced to 0 to indicate a write. 00111 * 00112 * @param address 8-bit I2C slave address [ addr | 0 ] 00113 * @param data Pointer to the byte-array data to send 00114 * @param length Number of bytes to send 00115 * @param repeated Repeated start, true - do not send stop at end 00116 * 00117 * @returns 00118 * 0 on success (ack), 00119 * non-0 on failure (nack) 00120 */ 00121 int write(int address, const char *data, int length, bool repeated = false); 00122 00123 /** Write single byte out on the I2C bus 00124 * 00125 * @param data data to write out on bus 00126 * 00127 * @returns 00128 * '1' if an ACK was received, 00129 * '0' otherwise 00130 */ 00131 int write(int data); 00132 00133 /** Creates a start condition on the I2C bus 00134 */ 00135 00136 void start(void); 00137 00138 /** Creates a stop condition on the I2C bus 00139 */ 00140 void stop(void); 00141 00142 /** Acquire exclusive access to this I2C bus 00143 */ 00144 virtual void lock(void); 00145 00146 /** Release exclusive access to this I2C bus 00147 */ 00148 virtual void unlock(void); 00149 00150 virtual ~I2C() { 00151 // Do nothing 00152 } 00153 00154 #if DEVICE_I2C_ASYNCH 00155 00156 /** Start non-blocking I2C transfer. 00157 * 00158 * @param address 8/10 bit I2c slave address 00159 * @param tx_buffer The TX buffer with data to be transfered 00160 * @param tx_length The length of TX buffer in bytes 00161 * @param rx_buffer The RX buffer which is used for received data 00162 * @param rx_length The length of RX buffer in bytes 00163 * @param event The logical OR of events to modify 00164 * @param callback The event callback function 00165 * @param repeated Repeated start, true - do not send stop at end 00166 * @return Zero if the transfer has started, or -1 if I2C peripheral is busy 00167 */ 00168 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); 00169 00170 /** Abort the on-going I2C transfer 00171 */ 00172 void abort_transfer(); 00173 protected: 00174 void irq_handler_asynch(void); 00175 event_callback_t _callback; 00176 CThunk<I2C> _irq; 00177 DMAUsage _usage; 00178 #endif 00179 00180 protected: 00181 void aquire(); 00182 00183 i2c_t _i2c; 00184 static I2C *_owner; 00185 int _hz; 00186 static SingletonPtr<PlatformMutex> _mutex; 00187 }; 00188 00189 } // namespace mbed 00190 00191 #endif 00192 00193 #endif
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