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Diff: drivers/I2C.h
- Revision:
- 149:156823d33999
diff -r 21d94c44109e -r 156823d33999 drivers/I2C.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/drivers/I2C.h Fri Oct 28 11:17:30 2016 +0100 @@ -0,0 +1,197 @@ +/* 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/platform.h" + +#if DEVICE_I2C + +#include "hal/i2c_api.h" +#include "platform/SingletonPtr.h" +#include "platform/PlatformMutex.h" + +#if DEVICE_I2C_ASYNCH +#include "platform/CThunk.h" +#include "hal/dma_api.h" +#include "platform/FunctionPointer.h" +#endif + +namespace mbed { +/** \addtogroup drivers */ +/** @{*/ + +/** An I2C Master, used for communicating with I2C slave devices + * + * @Note Synchronization level: Thread safe + * + * 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); + + /** Acquire exclusive access to this I2C bus + */ + virtual void lock(void); + + /** Release exclusive access to this I2C bus + */ + virtual void unlock(void); + + virtual ~I2C() { + // Do nothing + } + +#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; + static SingletonPtr<PlatformMutex> _mutex; +}; + +} // namespace mbed + +#endif + +#endif + +/** @}*/