tmk_core/tool/mbed/mbed-sdk/libraries/mbed/common/I2C.cpp

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #include "I2C.h"
  17
  18 #if DEVICE_I2C
  19
  20 namespace mbed {
  21
  22 I2C *I2C::_owner = NULL;
  23
  24 I2C::I2C(PinName sda, PinName scl) : _i2c(), _hz(100000) {
  25     // The init function also set the frequency to 100000
  26     i2c_init(&_i2c, sda, scl);
  27
  28     // Used to avoid unnecessary frequency updates
  29     _owner = this;
  30 }
  31
  32 void I2C::frequency(int hz) {
  33     _hz = hz;
  34
  35     // We want to update the frequency even if we are already the bus owners
  36     i2c_frequency(&_i2c, _hz);
  37
  38     // Updating the frequency of the bus we become the owners of it
  39     _owner = this;
  40 }
  41
  42 void I2C::aquire() {
  43     if (_owner != this) {
  44         i2c_frequency(&_i2c, _hz);
  45         _owner = this;
  46     }
  47 }
  48
  49 // write - Master Transmitter Mode
  50 int I2C::write(int address, const char* data, int length, bool repeated) {
  51     aquire();
  52
  53     int stop = (repeated) ? 0 : 1;
  54     int written = i2c_write(&_i2c, address, data, length, stop);
  55
  56     return length != written;
  57 }
  58
  59 int I2C::write(int data) {
  60     return i2c_byte_write(&_i2c, data);
  61 }
  62
  63 // read - Master Reciever Mode
  64 int I2C::read(int address, char* data, int length, bool repeated) {
  65     aquire();
  66
  67     int stop = (repeated) ? 0 : 1;
  68     int read = i2c_read(&_i2c, address, data, length, stop);
  69
  70     return length != read;
  71 }
  72
  73 int I2C::read(int ack) {
  74     if (ack) {
  75         return i2c_byte_read(&_i2c, 0);
  76     } else {
  77         return i2c_byte_read(&_i2c, 1);
  78     }
  79 }
  80
  81 void I2C::start(void) {
  82     i2c_start(&_i2c);
  83 }
  84
  85 void I2C::stop(void) {
  86     i2c_stop(&_i2c);
  87 }
  88
  89 } // namespace mbed
  90
  91 #endif