text: /* mbed Microcontroller Library
   * Copyright (c) 2006-2013 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_SLAVE_H
  #define MBED_I2C_SLAVE_H
  
  #include "platform/platform.h"
  
  #if DEVICE_I2CSLAVE
  
  #include "hal/i2c_api.h"
  
  namespace mbed {
  /** \addtogroup drivers */
  /** @{*/
  
  /** An I2C Slave, used for communicating with an I2C Master device
   *
   * @Note Synchronization level: Not protected
   *
   * Example:
   * @code
   * // Simple I2C responder
   * #include <mbed.h>
   *
   * I2CSlave slave(p9, p10);
   *
   * int main() {
   *     char buf[10];
   *     char msg[] = "Slave!";
   *
   *     slave.address(0xA0);
   *     while (1) {
   *         int i = slave.receive();
   *         switch (i) {
   *             case I2CSlave::ReadAddressed:
   *                 slave.write(msg, strlen(msg) + 1); // Includes null char
   *                 break;
   *             case I2CSlave::WriteGeneral:
   *                 slave.read(buf, 10);
   *                 printf("Read G: %s\n", buf);
   *                 break;
   *             case I2CSlave::WriteAddressed:
   *                 slave.read(buf, 10);
   *                 printf("Read A: %s\n", buf);
   *                 break;
   *         }
   *         for(int i = 0; i < 10; i++) buf[i] = 0;    // Clear buffer
   *     }
   * }
   * @endcode
   */
  class I2CSlave {
  
  public:
      enum RxStatus {
          NoData         = 0,
          ReadAddressed  = 1,
          WriteGeneral   = 2,
          WriteAddressed = 3
      };
  
      /** Create an I2C Slave interface, connected to the specified pins.
       *
       *  @param sda I2C data line pin
       *  @param scl I2C clock line pin
       */
      I2CSlave(PinName sda, PinName scl);
  
      /** Set the frequency of the I2C interface
       *
       *  @param hz The bus frequency in hertz
       */
      void frequency(int hz);
  
      /** Checks to see if this I2C Slave has been addressed.
       *
       *  @returns
       *  A status indicating if the device has been addressed, and how
       *  - NoData            - the slave has not been addressed
       *  - ReadAddressed     - the master has requested a read from this slave
       *  - WriteAddressed    - the master is writing to this slave
       *  - WriteGeneral      - the master is writing to all slave
       */
      int receive(void);
  
      /** Read from an I2C master.
       *
       *  @param data pointer to the byte array to read data in to
       *  @param length maximum number of bytes to read
       *
       *  @returns
       *       0 on success,
       *   non-0 otherwise
       */
      int read(char *data, int length);
  
      /** Read a single byte from an I2C master.
       *
       *  @returns
       *    the byte read
       */
      int read(void);
  
      /** Write to an I2C master.
       *
       *  @param data pointer to the byte array to be transmitted
       *  @param length the number of bytes to transmite
       *
       *  @returns
       *       0 on success,
       *   non-0 otherwise
       */
      int write(const char *data, int length);
  
      /** Write a single byte to an I2C master.
       *
       *  @data the byte to write
       *
       *  @returns
       *    '1' if an ACK was received,
       *    '0' otherwise
       */
      int write(int data);
  
      /** Sets the I2C slave address.
       *
       *  @param address The address to set for the slave (ignoring the least
       *  signifcant bit). If set to 0, the slave will only respond to the
       *  general call address.
       */
      void address(int address);
  
      /** Reset the I2C slave back into the known ready receiving state.
       */
      void stop(void);
  
  protected:
      i2c_t _i2c;
  };
  
  } // namespace mbed
  
  #endif
  
  #endif
  
  /** @}*/
  