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/* mbed Microcontroller Library
* Copyright (c) 2006-2015 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "I2C.h"
#if DEVICE_I2C
namespace mbed {
I2C *I2C::_owner = NULL;
I2C::I2C(PinName sda, PinName scl) :
#if DEVICE_I2C_ASYNCH
_irq(this), _usage(DMA_USAGE_NEVER),
#endif
_i2c(), _hz(100000) {
// The init function also set the frequency to 100000
i2c_init(&_i2c, sda, scl);
// Used to avoid unnecessary frequency updates
_owner = this;
}
void I2C::frequency(int hz) {
_hz = hz;
// We want to update the frequency even if we are already the bus owners
i2c_frequency(&_i2c, _hz);
// Updating the frequency of the bus we become the owners of it
_owner = this;
}
void I2C::aquire() {
if (_owner != this) {
i2c_frequency(&_i2c, _hz);
_owner = this;
}
}
// write - Master Transmitter Mode
int I2C::write(int address, const char* data, int length, bool repeated) {
aquire();
int stop = (repeated) ? 0 : 1;
int written = i2c_write(&_i2c, address, data, length, stop);
return length != written;
}
int I2C::write(int data) {
return i2c_byte_write(&_i2c, data);
}
// read - Master Reciever Mode
int I2C::read(int address, char* data, int length, bool repeated) {
aquire();
int stop = (repeated) ? 0 : 1;
int read = i2c_read(&_i2c, address, data, length, stop);
return length != read;
}
int I2C::read(int ack) {
if (ack) {
return i2c_byte_read(&_i2c, 0);
} else {
return i2c_byte_read(&_i2c, 1);
}
}
void I2C::start(void) {
i2c_start(&_i2c);
}
void I2C::stop(void) {
i2c_stop(&_i2c);
}
#if DEVICE_I2C_ASYNCH
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)
{
if (i2c_active(&_i2c)) {
return -1; // transaction ongoing
}
aquire();
_callback = callback;
int stop = (repeated) ? 0 : 1;
_irq.callback(&I2C::irq_handler_asynch);
i2c_transfer_asynch(&_i2c, (void *)tx_buffer, tx_length, (void *)rx_buffer, rx_length, address, stop, _irq.entry(), event, _usage);
return 0;
}
void I2C::abort_transfer(void)
{
i2c_abort_asynch(&_i2c);
}
void I2C::irq_handler_asynch(void)
{
int event = i2c_irq_handler_asynch(&_i2c);
if (_callback && event) {
_callback.call(event);
}
}
#endif
} // namespace mbed
#endif