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mbed-classic/api/I2C.h

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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.
*/
#ifndef MBED_I2C_H
#define MBED_I2C_H
#include "platform.h"
#if DEVICE_I2C
#include "i2c_api.h"
#if DEVICE_I2C_ASYNCH
#include "CThunk.h"
#include "dma_api.h"
#include "FunctionPointer.h"
#endif
namespace mbed {
/** An I2C Master, used for communicating with I2C slave devices
*
* Example:
* @code
* // Read from I2C slave at address 0x62
*
* #include "mbed.h"
*
* I2C i2c(p28, p27);
*
* int main() {
* int address = 0x62;
* char data[2];
* i2c.read(address, data, 2);
* }
* @endcode
*/
class I2C {
public:
enum RxStatus {
NoData,
MasterGeneralCall,
MasterWrite,
MasterRead
};
enum Acknowledge {
NoACK = 0,
ACK = 1
};
/** Create an I2C Master interface, connected to the specified pins
*
* @param sda I2C data line pin
* @param scl I2C clock line pin
*/
I2C(PinName sda, PinName scl);
/** Set the frequency of the I2C interface
*
* @param hz The bus frequency in hertz
*/
void frequency(int hz);
/** Read from an I2C slave
*
* Performs a complete read transaction. The bottom bit of
* the address is forced to 1 to indicate a read.
*
* @param address 8-bit I2C slave address [ addr | 1 ]
* @param data Pointer to the byte-array to read data in to
* @param length Number of bytes to read
* @param repeated Repeated start, true - don't send stop at end
*
* @returns
* 0 on success (ack),
* non-0 on failure (nack)
*/
int read(int address, char *data, int length, bool repeated = false);
/** Read a single byte from the I2C bus
*
* @param ack indicates if the byte is to be acknowledged (1 = acknowledge)
*
* @returns
* the byte read
*/
int read(int ack);
/** Write to an I2C slave
*
* Performs a complete write transaction. The bottom bit of
* the address is forced to 0 to indicate a write.
*
* @param address 8-bit I2C slave address [ addr | 0 ]
* @param data Pointer to the byte-array data to send
* @param length Number of bytes to send
* @param repeated Repeated start, true - do not send stop at end
*
* @returns
* 0 on success (ack),
* non-0 on failure (nack)
*/
int write(int address, const char *data, int length, bool repeated = false);
/** Write single byte out on the I2C bus
*
* @param data data to write out on bus
*
* @returns
* '1' if an ACK was received,
* '0' otherwise
*/
int write(int data);
/** Creates a start condition on the I2C bus
*/
void start(void);
/** Creates a stop condition on the I2C bus
*/
void stop(void);
#if DEVICE_I2C_ASYNCH
/** Start non-blocking I2C transfer.
*
* @param address 8/10 bit I2c slave address
* @param tx_buffer The TX buffer with data to be transfered
* @param tx_length The length of TX buffer in bytes
* @param rx_buffer The RX buffer which is used for received data
* @param rx_length The length of RX buffer in bytes
* @param event The logical OR of events to modify
* @param callback The event callback function
* @param repeated Repeated start, true - do not send stop at end
* @return Zero if the transfer has started, or -1 if I2C peripheral is busy
*/
int transfer(int address, const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length, const event_callback_t& callback, int event = I2C_EVENT_TRANSFER_COMPLETE, bool repeated = false);
/** Abort the on-going I2C transfer
*/
void abort_transfer();
protected:
void irq_handler_asynch(void);
event_callback_t _callback;
CThunk<I2C> _irq;
DMAUsage _usage;
#endif
protected:
void aquire();
i2c_t _i2c;
static I2C *_owner;
int _hz;
};
} // namespace mbed
#endif
#endif