Sergey Solodunov / mbed-dev

mbed library sources. Supersedes mbed-src.

Fork of mbed-dev by mbed official

common/I2C.cpp@0:9b334a45a8ff, 2015-10-01 (annotated)

Committer:
bogdanm
Date:
Thu Oct 01 15:25:22 2015 +0300
Revision:
0:9b334a45a8ff
Initial commit on mbed-dev



Replaces mbed-src (now inactive)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
bogdanm 0:9b334a45a8ff 1 /* mbed Microcontroller Library
bogdanm 0:9b334a45a8ff 2 * Copyright (c) 2006-2015 ARM Limited
bogdanm 0:9b334a45a8ff 3 *
bogdanm 0:9b334a45a8ff 4 * Licensed under the Apache License, Version 2.0 (the "License");
bogdanm 0:9b334a45a8ff 5 * you may not use this file except in compliance with the License.
bogdanm 0:9b334a45a8ff 6 * You may obtain a copy of the License at
bogdanm 0:9b334a45a8ff 7 *
bogdanm 0:9b334a45a8ff 8 * http://www.apache.org/licenses/LICENSE-2.0
bogdanm 0:9b334a45a8ff 9 *
bogdanm 0:9b334a45a8ff 10 * Unless required by applicable law or agreed to in writing, software
bogdanm 0:9b334a45a8ff 11 * distributed under the License is distributed on an "AS IS" BASIS,
bogdanm 0:9b334a45a8ff 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
bogdanm 0:9b334a45a8ff 13 * See the License for the specific language governing permissions and
bogdanm 0:9b334a45a8ff 14 * limitations under the License.
bogdanm 0:9b334a45a8ff 15 */
bogdanm 0:9b334a45a8ff 16 #include "I2C.h"
bogdanm 0:9b334a45a8ff 17
bogdanm 0:9b334a45a8ff 18 #if DEVICE_I2C
bogdanm 0:9b334a45a8ff 19
bogdanm 0:9b334a45a8ff 20 namespace mbed {
bogdanm 0:9b334a45a8ff 21
bogdanm 0:9b334a45a8ff 22 I2C *I2C::_owner = NULL;
bogdanm 0:9b334a45a8ff 23
bogdanm 0:9b334a45a8ff 24 I2C::I2C(PinName sda, PinName scl) :
bogdanm 0:9b334a45a8ff 25 #if DEVICE_I2C_ASYNCH
bogdanm 0:9b334a45a8ff 26 _irq(this), _usage(DMA_USAGE_NEVER),
bogdanm 0:9b334a45a8ff 27 #endif
bogdanm 0:9b334a45a8ff 28 _i2c(), _hz(100000) {
bogdanm 0:9b334a45a8ff 29 // The init function also set the frequency to 100000
bogdanm 0:9b334a45a8ff 30 i2c_init(&_i2c, sda, scl);
bogdanm 0:9b334a45a8ff 31
bogdanm 0:9b334a45a8ff 32 // Used to avoid unnecessary frequency updates
bogdanm 0:9b334a45a8ff 33 _owner = this;
bogdanm 0:9b334a45a8ff 34 }
bogdanm 0:9b334a45a8ff 35
bogdanm 0:9b334a45a8ff 36 void I2C::frequency(int hz) {
bogdanm 0:9b334a45a8ff 37 _hz = hz;
bogdanm 0:9b334a45a8ff 38
bogdanm 0:9b334a45a8ff 39 // We want to update the frequency even if we are already the bus owners
bogdanm 0:9b334a45a8ff 40 i2c_frequency(&_i2c, _hz);
bogdanm 0:9b334a45a8ff 41
bogdanm 0:9b334a45a8ff 42 // Updating the frequency of the bus we become the owners of it
bogdanm 0:9b334a45a8ff 43 _owner = this;
bogdanm 0:9b334a45a8ff 44 }
bogdanm 0:9b334a45a8ff 45
bogdanm 0:9b334a45a8ff 46 void I2C::aquire() {
bogdanm 0:9b334a45a8ff 47 if (_owner != this) {
bogdanm 0:9b334a45a8ff 48 i2c_frequency(&_i2c, _hz);
bogdanm 0:9b334a45a8ff 49 _owner = this;
bogdanm 0:9b334a45a8ff 50 }
bogdanm 0:9b334a45a8ff 51 }
bogdanm 0:9b334a45a8ff 52
bogdanm 0:9b334a45a8ff 53 // write - Master Transmitter Mode
bogdanm 0:9b334a45a8ff 54 int I2C::write(int address, const char* data, int length, bool repeated) {
bogdanm 0:9b334a45a8ff 55 aquire();
bogdanm 0:9b334a45a8ff 56
bogdanm 0:9b334a45a8ff 57 int stop = (repeated) ? 0 : 1;
bogdanm 0:9b334a45a8ff 58 int written = i2c_write(&_i2c, address, data, length, stop);
bogdanm 0:9b334a45a8ff 59
bogdanm 0:9b334a45a8ff 60 return length != written;
bogdanm 0:9b334a45a8ff 61 }
bogdanm 0:9b334a45a8ff 62
bogdanm 0:9b334a45a8ff 63 int I2C::write(int data) {
bogdanm 0:9b334a45a8ff 64 return i2c_byte_write(&_i2c, data);
bogdanm 0:9b334a45a8ff 65 }
bogdanm 0:9b334a45a8ff 66
bogdanm 0:9b334a45a8ff 67 // read - Master Reciever Mode
bogdanm 0:9b334a45a8ff 68 int I2C::read(int address, char* data, int length, bool repeated) {
bogdanm 0:9b334a45a8ff 69 aquire();
bogdanm 0:9b334a45a8ff 70
bogdanm 0:9b334a45a8ff 71 int stop = (repeated) ? 0 : 1;
bogdanm 0:9b334a45a8ff 72 int read = i2c_read(&_i2c, address, data, length, stop);
bogdanm 0:9b334a45a8ff 73
bogdanm 0:9b334a45a8ff 74 return length != read;
bogdanm 0:9b334a45a8ff 75 }
bogdanm 0:9b334a45a8ff 76
bogdanm 0:9b334a45a8ff 77 int I2C::read(int ack) {
bogdanm 0:9b334a45a8ff 78 if (ack) {
bogdanm 0:9b334a45a8ff 79 return i2c_byte_read(&_i2c, 0);
bogdanm 0:9b334a45a8ff 80 } else {
bogdanm 0:9b334a45a8ff 81 return i2c_byte_read(&_i2c, 1);
bogdanm 0:9b334a45a8ff 82 }
bogdanm 0:9b334a45a8ff 83 }
bogdanm 0:9b334a45a8ff 84
bogdanm 0:9b334a45a8ff 85 void I2C::start(void) {
bogdanm 0:9b334a45a8ff 86 i2c_start(&_i2c);
bogdanm 0:9b334a45a8ff 87 }
bogdanm 0:9b334a45a8ff 88
bogdanm 0:9b334a45a8ff 89 void I2C::stop(void) {
bogdanm 0:9b334a45a8ff 90 i2c_stop(&_i2c);
bogdanm 0:9b334a45a8ff 91 }
bogdanm 0:9b334a45a8ff 92
bogdanm 0:9b334a45a8ff 93 #if DEVICE_I2C_ASYNCH
bogdanm 0:9b334a45a8ff 94
bogdanm 0:9b334a45a8ff 95 int I2C::transfer(int address, const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length, const event_callback_t& callback, int event, bool repeated)
bogdanm 0:9b334a45a8ff 96 {
bogdanm 0:9b334a45a8ff 97 if (i2c_active(&_i2c)) {
bogdanm 0:9b334a45a8ff 98 return -1; // transaction ongoing
bogdanm 0:9b334a45a8ff 99 }
bogdanm 0:9b334a45a8ff 100 aquire();
bogdanm 0:9b334a45a8ff 101
bogdanm 0:9b334a45a8ff 102 _callback = callback;
bogdanm 0:9b334a45a8ff 103 int stop = (repeated) ? 0 : 1;
bogdanm 0:9b334a45a8ff 104 _irq.callback(&I2C::irq_handler_asynch);
bogdanm 0:9b334a45a8ff 105 i2c_transfer_asynch(&_i2c, (void *)tx_buffer, tx_length, (void *)rx_buffer, rx_length, address, stop, _irq.entry(), event, _usage);
bogdanm 0:9b334a45a8ff 106 return 0;
bogdanm 0:9b334a45a8ff 107 }
bogdanm 0:9b334a45a8ff 108
bogdanm 0:9b334a45a8ff 109 void I2C::abort_transfer(void)
bogdanm 0:9b334a45a8ff 110 {
bogdanm 0:9b334a45a8ff 111 i2c_abort_asynch(&_i2c);
bogdanm 0:9b334a45a8ff 112 }
bogdanm 0:9b334a45a8ff 113
bogdanm 0:9b334a45a8ff 114 void I2C::irq_handler_asynch(void)
bogdanm 0:9b334a45a8ff 115 {
bogdanm 0:9b334a45a8ff 116 int event = i2c_irq_handler_asynch(&_i2c);
bogdanm 0:9b334a45a8ff 117 if (_callback && event) {
bogdanm 0:9b334a45a8ff 118 _callback.call(event);
bogdanm 0:9b334a45a8ff 119 }
bogdanm 0:9b334a45a8ff 120
bogdanm 0:9b334a45a8ff 121 }
bogdanm 0:9b334a45a8ff 122
bogdanm 0:9b334a45a8ff 123
bogdanm 0:9b334a45a8ff 124 #endif
bogdanm 0:9b334a45a8ff 125
bogdanm 0:9b334a45a8ff 126 } // namespace mbed
bogdanm 0:9b334a45a8ff 127
bogdanm 0:9b334a45a8ff 128 #endif