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@13:0645d8841f51, 2013-08-05 (annotated)

Committer:
bogdanm
Date:
Mon Aug 05 14:12:34 2013 +0300
Revision:
13:0645d8841f51
Parent:
10:3bc89ef62ce7
Child:
212:34d62c0b2af6
Update mbed sources to revision 64

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 13:0645d8841f51 1 /* mbed Microcontroller Library
bogdanm 13:0645d8841f51 2 * Copyright (c) 2006-2013 ARM Limited
bogdanm 13:0645d8841f51 3 *
bogdanm 13:0645d8841f51 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 13:0645d8841f51 5 * you may not use this file except in compliance with the License.
bogdanm 13:0645d8841f51 6 * You may obtain a copy of the License at
bogdanm 13:0645d8841f51 7 *
bogdanm 13:0645d8841f51 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 13:0645d8841f51 9 *
bogdanm 13:0645d8841f51 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 13:0645d8841f51 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 13:0645d8841f51 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 13:0645d8841f51 13 * See the License for the specific language governing permissions and
bogdanm 13:0645d8841f51 14 * limitations under the License.
bogdanm 13:0645d8841f51 15 */
bogdanm 13:0645d8841f51 16 #include "I2C.h"
bogdanm 13:0645d8841f51 17
bogdanm 13:0645d8841f51 18 #if DEVICE_I2C
bogdanm 13:0645d8841f51 19
bogdanm 13:0645d8841f51 20 namespace mbed {
bogdanm 13:0645d8841f51 21
bogdanm 13:0645d8841f51 22 I2C *I2C::_owner = NULL;
bogdanm 13:0645d8841f51 23
bogdanm 13:0645d8841f51 24 I2C::I2C(PinName sda, PinName scl) {
bogdanm 13:0645d8841f51 25 // The init function also set the frequency to 100000
bogdanm 13:0645d8841f51 26 i2c_init(&_i2c, sda, scl);
bogdanm 13:0645d8841f51 27 _hz = 100000;
bogdanm 13:0645d8841f51 28
bogdanm 13:0645d8841f51 29 // Used to avoid unnecessary frequency updates
bogdanm 13:0645d8841f51 30 _owner = this;
bogdanm 13:0645d8841f51 31 }
bogdanm 13:0645d8841f51 32
bogdanm 13:0645d8841f51 33 void I2C::frequency(int hz) {
bogdanm 13:0645d8841f51 34 _hz = hz;
bogdanm 13:0645d8841f51 35
bogdanm 13:0645d8841f51 36 // We want to update the frequency even if we are already the bus owners
bogdanm 13:0645d8841f51 37 i2c_frequency(&_i2c, _hz);
bogdanm 13:0645d8841f51 38
bogdanm 13:0645d8841f51 39 // Updating the frequency of the bus we become the owners of it
bogdanm 13:0645d8841f51 40 _owner = this;
bogdanm 13:0645d8841f51 41 }
bogdanm 13:0645d8841f51 42
bogdanm 13:0645d8841f51 43 void I2C::aquire() {
bogdanm 13:0645d8841f51 44 if (_owner != this) {
bogdanm 13:0645d8841f51 45 i2c_frequency(&_i2c, _hz);
bogdanm 13:0645d8841f51 46 _owner = this;
bogdanm 13:0645d8841f51 47 }
bogdanm 13:0645d8841f51 48 }
bogdanm 13:0645d8841f51 49
bogdanm 13:0645d8841f51 50 // write - Master Transmitter Mode
bogdanm 13:0645d8841f51 51 int I2C::write(int address, const char* data, int length, bool repeated) {
bogdanm 13:0645d8841f51 52 aquire();
bogdanm 13:0645d8841f51 53
bogdanm 13:0645d8841f51 54 int stop = (repeated) ? 0 : 1;
bogdanm 13:0645d8841f51 55 int written = i2c_write(&_i2c, address, data, length, stop);
bogdanm 13:0645d8841f51 56
bogdanm 13:0645d8841f51 57 return length != written;
bogdanm 13:0645d8841f51 58 }
bogdanm 13:0645d8841f51 59
bogdanm 13:0645d8841f51 60 int I2C::write(int data) {
bogdanm 13:0645d8841f51 61 return i2c_byte_write(&_i2c, data);
bogdanm 13:0645d8841f51 62 }
bogdanm 13:0645d8841f51 63
bogdanm 13:0645d8841f51 64 // read - Master Reciever Mode
bogdanm 13:0645d8841f51 65 int I2C::read(int address, char* data, int length, bool repeated) {
bogdanm 13:0645d8841f51 66 aquire();
bogdanm 13:0645d8841f51 67
bogdanm 13:0645d8841f51 68 int stop = (repeated) ? 0 : 1;
bogdanm 13:0645d8841f51 69 int read = i2c_read(&_i2c, address, data, length, stop);
bogdanm 13:0645d8841f51 70
bogdanm 13:0645d8841f51 71 return length != read;
bogdanm 13:0645d8841f51 72 }
bogdanm 13:0645d8841f51 73
bogdanm 13:0645d8841f51 74 int I2C::read(int ack) {
bogdanm 13:0645d8841f51 75 if (ack) {
bogdanm 13:0645d8841f51 76 return i2c_byte_read(&_i2c, 0);
bogdanm 13:0645d8841f51 77 } else {
bogdanm 13:0645d8841f51 78 return i2c_byte_read(&_i2c, 1);
bogdanm 13:0645d8841f51 79 }
bogdanm 13:0645d8841f51 80 }
bogdanm 13:0645d8841f51 81
bogdanm 13:0645d8841f51 82 void I2C::start(void) {
bogdanm 13:0645d8841f51 83 i2c_start(&_i2c);
bogdanm 13:0645d8841f51 84 }
bogdanm 13:0645d8841f51 85
bogdanm 13:0645d8841f51 86 void I2C::stop(void) {
bogdanm 13:0645d8841f51 87 i2c_stop(&_i2c);
bogdanm 13:0645d8841f51 88 }
bogdanm 13:0645d8841f51 89
bogdanm 13:0645d8841f51 90 } // namespace mbed
bogdanm 13:0645d8841f51 91
bogdanm 13:0645d8841f51 92 #endif