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mbed/I2C.h 4.67 KB
f7c9a8e1   jdenecha   Feat : Firt dump
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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