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

cpp/I2C.cpp@0:fd0d7bdfcdc2, 2012-11-20 (annotated)

Committer:
mbed_official
Date:
Tue Nov 20 17:24:08 2012 +0000
Revision:
0:fd0d7bdfcdc2
Child:
2:143cac498751
mbed sources

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 0:fd0d7bdfcdc2 1 /* mbed Microcontroller Library
mbed_official 0:fd0d7bdfcdc2 2 * Copyright (c) 2006-2012 ARM Limited
mbed_official 0:fd0d7bdfcdc2 3 *
mbed_official 0:fd0d7bdfcdc2 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
mbed_official 0:fd0d7bdfcdc2 5 * of this software and associated documentation files (the "Software"), to deal
mbed_official 0:fd0d7bdfcdc2 6 * in the Software without restriction, including without limitation the rights
mbed_official 0:fd0d7bdfcdc2 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
mbed_official 0:fd0d7bdfcdc2 8 * copies of the Software, and to permit persons to whom the Software is
mbed_official 0:fd0d7bdfcdc2 9 * furnished to do so, subject to the following conditions:
mbed_official 0:fd0d7bdfcdc2 10 *
mbed_official 0:fd0d7bdfcdc2 11 * The above copyright notice and this permission notice shall be included in
mbed_official 0:fd0d7bdfcdc2 12 * all copies or substantial portions of the Software.
mbed_official 0:fd0d7bdfcdc2 13 *
mbed_official 0:fd0d7bdfcdc2 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
mbed_official 0:fd0d7bdfcdc2 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
mbed_official 0:fd0d7bdfcdc2 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
mbed_official 0:fd0d7bdfcdc2 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
mbed_official 0:fd0d7bdfcdc2 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
mbed_official 0:fd0d7bdfcdc2 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
mbed_official 0:fd0d7bdfcdc2 20 * SOFTWARE.
mbed_official 0:fd0d7bdfcdc2 21 */
mbed_official 0:fd0d7bdfcdc2 22 #include "I2C.h"
mbed_official 0:fd0d7bdfcdc2 23
mbed_official 0:fd0d7bdfcdc2 24 #if DEVICE_I2C
mbed_official 0:fd0d7bdfcdc2 25
mbed_official 0:fd0d7bdfcdc2 26 namespace mbed {
mbed_official 0:fd0d7bdfcdc2 27
mbed_official 0:fd0d7bdfcdc2 28 I2C *I2C::_owner = NULL;
mbed_official 0:fd0d7bdfcdc2 29
mbed_official 0:fd0d7bdfcdc2 30 I2C::I2C(PinName sda, PinName scl) {
mbed_official 0:fd0d7bdfcdc2 31 // The init function also set the frequency to 100000
mbed_official 0:fd0d7bdfcdc2 32 i2c_init(&_i2c, sda, scl);
mbed_official 0:fd0d7bdfcdc2 33 _hz = 100000;
mbed_official 0:fd0d7bdfcdc2 34
mbed_official 0:fd0d7bdfcdc2 35 // Used to avoid unnecessary frequency updates
mbed_official 0:fd0d7bdfcdc2 36 _owner = this;
mbed_official 0:fd0d7bdfcdc2 37 }
mbed_official 0:fd0d7bdfcdc2 38
mbed_official 0:fd0d7bdfcdc2 39 void I2C::frequency(int hz) {
mbed_official 0:fd0d7bdfcdc2 40 _hz = hz;
mbed_official 0:fd0d7bdfcdc2 41
mbed_official 0:fd0d7bdfcdc2 42 // We want to update the frequency even if we are already the bus owners
mbed_official 0:fd0d7bdfcdc2 43 i2c_frequency(&_i2c, _hz);
mbed_official 0:fd0d7bdfcdc2 44
mbed_official 0:fd0d7bdfcdc2 45 // Updating the frequency of the bus we become the owners of it
mbed_official 0:fd0d7bdfcdc2 46 _owner = this;
mbed_official 0:fd0d7bdfcdc2 47 }
mbed_official 0:fd0d7bdfcdc2 48
mbed_official 0:fd0d7bdfcdc2 49 void I2C::aquire() {
mbed_official 0:fd0d7bdfcdc2 50 if (_owner != this) {
mbed_official 0:fd0d7bdfcdc2 51 i2c_frequency(&_i2c, _hz);
mbed_official 0:fd0d7bdfcdc2 52 _owner = this;
mbed_official 0:fd0d7bdfcdc2 53 }
mbed_official 0:fd0d7bdfcdc2 54 }
mbed_official 0:fd0d7bdfcdc2 55
mbed_official 0:fd0d7bdfcdc2 56 // write - Master Transmitter Mode
mbed_official 0:fd0d7bdfcdc2 57 int I2C::write(int address, const char* data, int length, bool repeated) {
mbed_official 0:fd0d7bdfcdc2 58 aquire();
mbed_official 0:fd0d7bdfcdc2 59
mbed_official 0:fd0d7bdfcdc2 60 int stop = (repeated) ? 0 : 1;
mbed_official 0:fd0d7bdfcdc2 61 int retval = i2c_write(&_i2c, address, data, length, stop);
mbed_official 0:fd0d7bdfcdc2 62
mbed_official 0:fd0d7bdfcdc2 63 return retval;
mbed_official 0:fd0d7bdfcdc2 64 }
mbed_official 0:fd0d7bdfcdc2 65
mbed_official 0:fd0d7bdfcdc2 66 int I2C::write(int data) {
mbed_official 0:fd0d7bdfcdc2 67 return i2c_byte_write(&_i2c, data);
mbed_official 0:fd0d7bdfcdc2 68 }
mbed_official 0:fd0d7bdfcdc2 69
mbed_official 0:fd0d7bdfcdc2 70 // read - Master Reciever Mode
mbed_official 0:fd0d7bdfcdc2 71 int I2C::read(int address, char* data, int length, bool repeated) {
mbed_official 0:fd0d7bdfcdc2 72 aquire();
mbed_official 0:fd0d7bdfcdc2 73
mbed_official 0:fd0d7bdfcdc2 74 int stop = (repeated) ? 0 : 1;
mbed_official 0:fd0d7bdfcdc2 75 int retval = i2c_read(&_i2c, address, data, length, stop);
mbed_official 0:fd0d7bdfcdc2 76
mbed_official 0:fd0d7bdfcdc2 77 return retval;
mbed_official 0:fd0d7bdfcdc2 78 }
mbed_official 0:fd0d7bdfcdc2 79
mbed_official 0:fd0d7bdfcdc2 80 int I2C::read(int ack) {
mbed_official 0:fd0d7bdfcdc2 81 if (ack) {
mbed_official 0:fd0d7bdfcdc2 82 return i2c_byte_read(&_i2c, 0);
mbed_official 0:fd0d7bdfcdc2 83 } else {
mbed_official 0:fd0d7bdfcdc2 84 return i2c_byte_read(&_i2c, 1);
mbed_official 0:fd0d7bdfcdc2 85 }
mbed_official 0:fd0d7bdfcdc2 86 }
mbed_official 0:fd0d7bdfcdc2 87
mbed_official 0:fd0d7bdfcdc2 88 void I2C::start(void) {
mbed_official 0:fd0d7bdfcdc2 89 i2c_start(&_i2c);
mbed_official 0:fd0d7bdfcdc2 90 }
mbed_official 0:fd0d7bdfcdc2 91
mbed_official 0:fd0d7bdfcdc2 92 void I2C::stop(void) {
mbed_official 0:fd0d7bdfcdc2 93 i2c_stop(&_i2c);
mbed_official 0:fd0d7bdfcdc2 94 }
mbed_official 0:fd0d7bdfcdc2 95
mbed_official 0:fd0d7bdfcdc2 96 } // namespace mbed
mbed_official 0:fd0d7bdfcdc2 97
mbed_official 0:fd0d7bdfcdc2 98 #endif