Ermanno Brusadin / mbed-src

mbed library sources

common/I2C.cpp@0:0a673c671a56, 2016-07-27 (annotated)

Committer:
ebrus
Date:
Wed Jul 27 18:35:32 2016 +0000
Revision:
0:0a673c671a56
4

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ebrus 0:0a673c671a56 1 /* mbed Microcontroller Library
ebrus 0:0a673c671a56 2 * Copyright (c) 2006-2013 ARM Limited
ebrus 0:0a673c671a56 3 *
ebrus 0:0a673c671a56 4 * Licensed under the Apache License, Version 2.0 (the "License");
ebrus 0:0a673c671a56 5 * you may not use this file except in compliance with the License.
ebrus 0:0a673c671a56 6 * You may obtain a copy of the License at
ebrus 0:0a673c671a56 7 *
ebrus 0:0a673c671a56 8 * http://www.apache.org/licenses/LICENSE-2.0
ebrus 0:0a673c671a56 9 *
ebrus 0:0a673c671a56 10 * Unless required by applicable law or agreed to in writing, software
ebrus 0:0a673c671a56 11 * distributed under the License is distributed on an "AS IS" BASIS,
ebrus 0:0a673c671a56 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
ebrus 0:0a673c671a56 13 * See the License for the specific language governing permissions and
ebrus 0:0a673c671a56 14 * limitations under the License.
ebrus 0:0a673c671a56 15 */
ebrus 0:0a673c671a56 16 #include "I2C.h"
ebrus 0:0a673c671a56 17
ebrus 0:0a673c671a56 18 #if DEVICE_I2C
ebrus 0:0a673c671a56 19
ebrus 0:0a673c671a56 20 namespace mbed {
ebrus 0:0a673c671a56 21
ebrus 0:0a673c671a56 22 I2C *I2C::_owner = NULL;
ebrus 0:0a673c671a56 23
ebrus 0:0a673c671a56 24 I2C::I2C(PinName sda, PinName scl) : _i2c(), _hz(100000) {
ebrus 0:0a673c671a56 25 // The init function also set the frequency to 100000
ebrus 0:0a673c671a56 26 i2c_init(&_i2c, sda, scl);
ebrus 0:0a673c671a56 27
ebrus 0:0a673c671a56 28 // Used to avoid unnecessary frequency updates
ebrus 0:0a673c671a56 29 _owner = this;
ebrus 0:0a673c671a56 30 }
ebrus 0:0a673c671a56 31
ebrus 0:0a673c671a56 32 void I2C::frequency(int hz) {
ebrus 0:0a673c671a56 33 _hz = hz;
ebrus 0:0a673c671a56 34
ebrus 0:0a673c671a56 35 // We want to update the frequency even if we are already the bus owners
ebrus 0:0a673c671a56 36 i2c_frequency(&_i2c, _hz);
ebrus 0:0a673c671a56 37
ebrus 0:0a673c671a56 38 // Updating the frequency of the bus we become the owners of it
ebrus 0:0a673c671a56 39 _owner = this;
ebrus 0:0a673c671a56 40 }
ebrus 0:0a673c671a56 41
ebrus 0:0a673c671a56 42 void I2C::aquire() {
ebrus 0:0a673c671a56 43 if (_owner != this) {
ebrus 0:0a673c671a56 44 i2c_frequency(&_i2c, _hz);
ebrus 0:0a673c671a56 45 _owner = this;
ebrus 0:0a673c671a56 46 }
ebrus 0:0a673c671a56 47 }
ebrus 0:0a673c671a56 48
ebrus 0:0a673c671a56 49 // write - Master Transmitter Mode
ebrus 0:0a673c671a56 50 int I2C::write(int address, const char* data, int length, bool repeated) {
ebrus 0:0a673c671a56 51 aquire();
ebrus 0:0a673c671a56 52
ebrus 0:0a673c671a56 53 int stop = (repeated) ? 0 : 1;
ebrus 0:0a673c671a56 54 int written = i2c_write(&_i2c, address, data, length, stop);
ebrus 0:0a673c671a56 55
ebrus 0:0a673c671a56 56 return length != written;
ebrus 0:0a673c671a56 57 }
ebrus 0:0a673c671a56 58
ebrus 0:0a673c671a56 59 int I2C::write(int data) {
ebrus 0:0a673c671a56 60 return i2c_byte_write(&_i2c, data);
ebrus 0:0a673c671a56 61 }
ebrus 0:0a673c671a56 62
ebrus 0:0a673c671a56 63 // read - Master Reciever Mode
ebrus 0:0a673c671a56 64 int I2C::read(int address, char* data, int length, bool repeated) {
ebrus 0:0a673c671a56 65 aquire();
ebrus 0:0a673c671a56 66
ebrus 0:0a673c671a56 67 int stop = (repeated) ? 0 : 1;
ebrus 0:0a673c671a56 68 int read = i2c_read(&_i2c, address, data, length, stop);
ebrus 0:0a673c671a56 69
ebrus 0:0a673c671a56 70 return length != read;
ebrus 0:0a673c671a56 71 }
ebrus 0:0a673c671a56 72
ebrus 0:0a673c671a56 73 int I2C::read(int ack) {
ebrus 0:0a673c671a56 74 if (ack) {
ebrus 0:0a673c671a56 75 return i2c_byte_read(&_i2c, 0);
ebrus 0:0a673c671a56 76 } else {
ebrus 0:0a673c671a56 77 return i2c_byte_read(&_i2c, 1);
ebrus 0:0a673c671a56 78 }
ebrus 0:0a673c671a56 79 }
ebrus 0:0a673c671a56 80
ebrus 0:0a673c671a56 81 void I2C::start(void) {
ebrus 0:0a673c671a56 82 i2c_start(&_i2c);
ebrus 0:0a673c671a56 83 }
ebrus 0:0a673c671a56 84
ebrus 0:0a673c671a56 85 void I2C::stop(void) {
ebrus 0:0a673c671a56 86 i2c_stop(&_i2c);
ebrus 0:0a673c671a56 87 }
ebrus 0:0a673c671a56 88
ebrus 0:0a673c671a56 89 } // namespace mbed
ebrus 0:0a673c671a56 90
ebrus 0:0a673c671a56 91 #endif