Lancaster University / mbed-src

Lancaster University's (short term!) clone of mbed-src for micro:bit. This is a copy of the github branch https://github.com/lancaster-university/mbed-classic

Fork of mbed-src by mbed official

common/I2C.cpp@10:3bc89ef62ce7, 2013-06-14 (annotated)

Committer:
emilmont
Date:
Fri Jun 14 17:49:17 2013 +0100
Revision:
10:3bc89ef62ce7
Parent:
9:0ce32e54c9a7
Child:
13:0645d8841f51
Unify mbed library sources

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emilmont 10:3bc89ef62ce7 1 /* mbed Microcontroller Library
emilmont 10:3bc89ef62ce7 2 * Copyright (c) 2006-2013 ARM Limited
emilmont 10:3bc89ef62ce7 3 *
emilmont 10:3bc89ef62ce7 4 * Licensed under the Apache License, Version 2.0 (the "License");
emilmont 10:3bc89ef62ce7 5 * you may not use this file except in compliance with the License.
emilmont 10:3bc89ef62ce7 6 * You may obtain a copy of the License at
emilmont 10:3bc89ef62ce7 7 *
emilmont 10:3bc89ef62ce7 8 * http://www.apache.org/licenses/LICENSE-2.0
emilmont 10:3bc89ef62ce7 9 *
emilmont 10:3bc89ef62ce7 10 * Unless required by applicable law or agreed to in writing, software
emilmont 10:3bc89ef62ce7 11 * distributed under the License is distributed on an "AS IS" BASIS,
emilmont 10:3bc89ef62ce7 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
emilmont 10:3bc89ef62ce7 13 * See the License for the specific language governing permissions and
emilmont 10:3bc89ef62ce7 14 * limitations under the License.
emilmont 10:3bc89ef62ce7 15 */
emilmont 10:3bc89ef62ce7 16 #include "I2C.h"
emilmont 10:3bc89ef62ce7 17
emilmont 10:3bc89ef62ce7 18 #if DEVICE_I2C
emilmont 10:3bc89ef62ce7 19
emilmont 10:3bc89ef62ce7 20 namespace mbed {
emilmont 10:3bc89ef62ce7 21
emilmont 10:3bc89ef62ce7 22 I2C *I2C::_owner = NULL;
emilmont 10:3bc89ef62ce7 23
emilmont 10:3bc89ef62ce7 24 I2C::I2C(PinName sda, PinName scl) {
emilmont 10:3bc89ef62ce7 25 // The init function also set the frequency to 100000
emilmont 10:3bc89ef62ce7 26 i2c_init(&_i2c, sda, scl);
emilmont 10:3bc89ef62ce7 27 _hz = 100000;
emilmont 10:3bc89ef62ce7 28
emilmont 10:3bc89ef62ce7 29 // Used to avoid unnecessary frequency updates
emilmont 10:3bc89ef62ce7 30 _owner = this;
emilmont 10:3bc89ef62ce7 31 }
emilmont 10:3bc89ef62ce7 32
emilmont 10:3bc89ef62ce7 33 void I2C::frequency(int hz) {
emilmont 10:3bc89ef62ce7 34 _hz = hz;
emilmont 10:3bc89ef62ce7 35
emilmont 10:3bc89ef62ce7 36 // We want to update the frequency even if we are already the bus owners
emilmont 10:3bc89ef62ce7 37 i2c_frequency(&_i2c, _hz);
emilmont 10:3bc89ef62ce7 38
emilmont 10:3bc89ef62ce7 39 // Updating the frequency of the bus we become the owners of it
emilmont 10:3bc89ef62ce7 40 _owner = this;
emilmont 10:3bc89ef62ce7 41 }
emilmont 10:3bc89ef62ce7 42
emilmont 10:3bc89ef62ce7 43 void I2C::aquire() {
emilmont 10:3bc89ef62ce7 44 if (_owner != this) {
emilmont 10:3bc89ef62ce7 45 i2c_frequency(&_i2c, _hz);
emilmont 10:3bc89ef62ce7 46 _owner = this;
emilmont 10:3bc89ef62ce7 47 }
emilmont 10:3bc89ef62ce7 48 }
emilmont 10:3bc89ef62ce7 49
emilmont 10:3bc89ef62ce7 50 // write - Master Transmitter Mode
emilmont 10:3bc89ef62ce7 51 int I2C::write(int address, const char* data, int length, bool repeated) {
emilmont 10:3bc89ef62ce7 52 aquire();
emilmont 10:3bc89ef62ce7 53
emilmont 10:3bc89ef62ce7 54 int stop = (repeated) ? 0 : 1;
emilmont 10:3bc89ef62ce7 55 int retval = i2c_write(&_i2c, address, data, length, stop);
emilmont 10:3bc89ef62ce7 56
emilmont 10:3bc89ef62ce7 57 return retval;
emilmont 10:3bc89ef62ce7 58 }
emilmont 10:3bc89ef62ce7 59
emilmont 10:3bc89ef62ce7 60 int I2C::write(int data) {
emilmont 10:3bc89ef62ce7 61 return i2c_byte_write(&_i2c, data);
emilmont 10:3bc89ef62ce7 62 }
emilmont 10:3bc89ef62ce7 63
emilmont 10:3bc89ef62ce7 64 // read - Master Reciever Mode
emilmont 10:3bc89ef62ce7 65 int I2C::read(int address, char* data, int length, bool repeated) {
emilmont 10:3bc89ef62ce7 66 aquire();
emilmont 10:3bc89ef62ce7 67
emilmont 10:3bc89ef62ce7 68 int stop = (repeated) ? 0 : 1;
emilmont 10:3bc89ef62ce7 69 int retval = i2c_read(&_i2c, address, data, length, stop);
emilmont 10:3bc89ef62ce7 70
emilmont 10:3bc89ef62ce7 71 return retval;
emilmont 10:3bc89ef62ce7 72 }
emilmont 10:3bc89ef62ce7 73
emilmont 10:3bc89ef62ce7 74 int I2C::read(int ack) {
emilmont 10:3bc89ef62ce7 75 if (ack) {
emilmont 10:3bc89ef62ce7 76 return i2c_byte_read(&_i2c, 0);
emilmont 10:3bc89ef62ce7 77 } else {
emilmont 10:3bc89ef62ce7 78 return i2c_byte_read(&_i2c, 1);
emilmont 10:3bc89ef62ce7 79 }
emilmont 10:3bc89ef62ce7 80 }
emilmont 10:3bc89ef62ce7 81
emilmont 10:3bc89ef62ce7 82 void I2C::start(void) {
emilmont 10:3bc89ef62ce7 83 i2c_start(&_i2c);
emilmont 10:3bc89ef62ce7 84 }
emilmont 10:3bc89ef62ce7 85
emilmont 10:3bc89ef62ce7 86 void I2C::stop(void) {
emilmont 10:3bc89ef62ce7 87 i2c_stop(&_i2c);
emilmont 10:3bc89ef62ce7 88 }
emilmont 10:3bc89ef62ce7 89
emilmont 10:3bc89ef62ce7 90 } // namespace mbed
emilmont 10:3bc89ef62ce7 91
emilmont 10:3bc89ef62ce7 92 #endif