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I2C.h
00001 /* mbed Microcontroller Library 00002 * Copyright (c) 2006-2013 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 00025 namespace mbed { 00026 00027 /** An I2C Master, used for communicating with I2C slave devices 00028 * 00029 * Example: 00030 * @code 00031 * // Read from I2C slave at address 0x62 00032 * 00033 * #include "mbed.h" 00034 * 00035 * I2C i2c(p28, p27); 00036 * 00037 * int main() { 00038 * int address = 0x62; 00039 * char data[2]; 00040 * i2c.read(address, data, 2); 00041 * } 00042 * @endcode 00043 */ 00044 class I2C { 00045 00046 public: 00047 enum RxStatus { 00048 NoData, 00049 MasterGeneralCall, 00050 MasterWrite, 00051 MasterRead 00052 }; 00053 00054 enum Acknowledge { 00055 NoACK = 0, 00056 ACK = 1 00057 }; 00058 00059 /** Create an I2C Master interface, connected to the specified pins 00060 * 00061 * @param sda I2C data line pin 00062 * @param scl I2C clock line pin 00063 */ 00064 I2C(PinName sda, PinName scl); 00065 00066 /** Set the frequency of the I2C interface 00067 * 00068 * @param hz The bus frequency in hertz 00069 */ 00070 void frequency(int hz); 00071 00072 /** Read from an I2C slave 00073 * 00074 * Performs a complete read transaction. The bottom bit of 00075 * the address is forced to 1 to indicate a read. 00076 * 00077 * @param address 8-bit I2C slave address [ addr | 1 ] 00078 * @param data Pointer to the byte-array to read data in to 00079 * @param length Number of bytes to read 00080 * @param repeated Repeated start, true - don't send stop at end 00081 * 00082 * @returns 00083 * 0 on success (ack), 00084 * non-0 on failure (nack) 00085 */ 00086 int read(int address, char *data, int length, bool repeated = false); 00087 00088 /** Read a single byte from the I2C bus 00089 * 00090 * @param ack indicates if the byte is to be acknowledged (1 = acknowledge) 00091 * 00092 * @returns 00093 * the byte read 00094 */ 00095 int read(int ack); 00096 00097 /** Write to an I2C slave 00098 * 00099 * Performs a complete write transaction. The bottom bit of 00100 * the address is forced to 0 to indicate a write. 00101 * 00102 * @param address 8-bit I2C slave address [ addr | 0 ] 00103 * @param data Pointer to the byte-array data to send 00104 * @param length Number of bytes to send 00105 * @param repeated Repeated start, true - do not send stop at end 00106 * 00107 * @returns 00108 * 0 on success (ack), 00109 * non-0 on failure (nack) 00110 */ 00111 int write(int address, const char *data, int length, bool repeated = false); 00112 00113 /** Write single byte out on the I2C bus 00114 * 00115 * @param data data to write out on bus 00116 * 00117 * @returns 00118 * '1' if an ACK was received, 00119 * '0' otherwise 00120 */ 00121 int write(int data); 00122 00123 /** Creates a start condition on the I2C bus 00124 */ 00125 00126 void start(void); 00127 00128 /** Creates a stop condition on the I2C bus 00129 */ 00130 void stop(void); 00131 00132 protected: 00133 void aquire(); 00134 00135 i2c_t _i2c; 00136 static I2C *_owner; 00137 int _hz; 00138 }; 00139 00140 } // namespace mbed 00141 00142 #endif 00143 00144 #endif
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