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I2C.cpp
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 #include "I2C.h" 00017 00018 #if DEVICE_I2C 00019 00020 namespace mbed { 00021 00022 I2C *I2C::_owner = NULL; 00023 00024 I2C::I2C(PinName sda, PinName scl) { 00025 // The init function also set the frequency to 100000 00026 i2c_init(&_i2c, sda, scl); 00027 _hz = 100000; 00028 00029 // Used to avoid unnecessary frequency updates 00030 _owner = this; 00031 } 00032 00033 void I2C::frequency(int hz) { 00034 _hz = hz; 00035 00036 // We want to update the frequency even if we are already the bus owners 00037 i2c_frequency(&_i2c, _hz); 00038 00039 // Updating the frequency of the bus we become the owners of it 00040 _owner = this; 00041 } 00042 00043 void I2C::aquire() { 00044 if (_owner != this) { 00045 i2c_frequency(&_i2c, _hz); 00046 _owner = this; 00047 } 00048 } 00049 00050 // write - Master Transmitter Mode 00051 int I2C::write(int address, const char* data, int length, bool repeated) { 00052 aquire(); 00053 00054 int stop = (repeated) ? 0 : 1; 00055 int written = i2c_write(&_i2c, address, data, length, stop); 00056 00057 return length != written; 00058 } 00059 00060 int I2C::write(int data) { 00061 return i2c_byte_write(&_i2c, data); 00062 } 00063 00064 // read - Master Reciever Mode 00065 int I2C::read(int address, char* data, int length, bool repeated) { 00066 aquire(); 00067 00068 int stop = (repeated) ? 0 : 1; 00069 int read = i2c_read(&_i2c, address, data, length, stop); 00070 00071 return length != read; 00072 } 00073 00074 int I2C::read(int ack) { 00075 if (ack) { 00076 return i2c_byte_read(&_i2c, 0); 00077 } else { 00078 return i2c_byte_read(&_i2c, 1); 00079 } 00080 } 00081 00082 void I2C::start(void) { 00083 i2c_start(&_i2c); 00084 } 00085 00086 void I2C::stop(void) { 00087 i2c_stop(&_i2c); 00088 } 00089 00090 } // namespace mbed 00091 00092 #endif
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