DevI2C.h

00001 /**
00002  ******************************************************************************
00003  * @file    DevI2C.h
00004  * @author  AST / EST / AMG-CL
00005  * @version V0.0.2
00006  * @date    25-July-2016
00007  * @brief   Header file for a special I2C class DevI2C which provides some
00008  *          helper function for on-board communication
00009  ******************************************************************************
00010  * @attention
00011  *
00012  * <h2><center>&copy; COPYRIGHT(c) 2014 STMicroelectronics</center></h2>
00013  *
00014  * Redistribution and use in source and binary forms, with or without modification,
00015  * are permitted provided that the following conditions are met:
00016  *   1. Redistributions of source code must retain the above copyright notice,
00017  *      this list of conditions and the following disclaimer.
00018  *   2. Redistributions in binary form must reproduce the above copyright notice,
00019  *      this list of conditions and the following disclaimer in the documentation
00020  *      and/or other materials provided with the distribution.
00021  *   3. Neither the name of STMicroelectronics nor the names of its contributors
00022  *      may be used to endorse or promote products derived from this software
00023  *      without specific prior written permission.
00024  *
00025  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
00026  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00027  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
00028  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
00029  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00030  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
00031  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00032  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
00033  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
00034  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00035  *
00036  ******************************************************************************
00037  */
00038 
00039 /* Define to prevent from recursive inclusion --------------------------------*/
00040 #ifndef __DEV_I2C_H
00041 #define __DEV_I2C_H
00042 
00043 /* Includes ------------------------------------------------------------------*/
00044 #include "mbed.h"
00045 
00046 /* Classes -------------------------------------------------------------------*/
00047 /** Helper class DevI2C providing functions for multi-register I2C communication
00048  *  common for a series of I2C devices
00049  */
00050 class DevI2C : public I2C
00051 {
00052  public:
00053    
00054    /** Create a DevI2C Master interface, connected to the specified pins
00055    *
00056    *  @param sda I2C data line pin
00057    *  @param scl I2C clock line pin
00058    */
00059    DevI2C(PinName sda, PinName scl) : I2C(sda, scl) {}
00060 
00061    /**
00062    * @brief  Writes a buffer towards the I2C peripheral device.
00063    * @param  pBuffer pointer to the byte-array data to send
00064    * @param  DeviceAddr specifies the peripheral device slave address.
00065    * @param  RegisterAddr specifies the internal address register 
00066    *         where to start writing to (must be correctly masked).
00067    * @param  NumByteToWrite number of bytes to be written.
00068    * @retval 0 if ok, 
00069    * @retval -1 if an I2C error has occured, or
00070    * @retval -2 on temporary buffer overflow (i.e. NumByteToWrite was too high)
00071    * @note   On some devices if NumByteToWrite is greater
00072    *         than one, the RegisterAddr must be masked correctly!
00073    */
00074    int i2c_write(uint8_t* pBuffer, uint8_t DeviceAddr, uint8_t RegisterAddr, 
00075                  uint16_t NumByteToWrite)
00076    {
00077      int ret;
00078      uint8_t tmp[TEMP_BUF_SIZE];
00079      
00080      if(NumByteToWrite >= TEMP_BUF_SIZE) return -2;
00081      
00082      /* First, send device address. Then, send data and STOP condition */
00083      tmp[0] = RegisterAddr;
00084      memcpy(tmp+1, pBuffer, NumByteToWrite);
00085      
00086      ret = write(DeviceAddr, (const char*)tmp, NumByteToWrite+1, false);
00087      
00088      if(ret) return -1;
00089      return 0;
00090    }
00091         
00092    /**
00093    * @brief  Writes a buffer towards the I2C peripheral device.
00094    * @param  pBuffer pointer to the byte-array data to send
00095    * @param  DeviceAddr specifies the peripheral device slave address.
00096    * @param  RegisterAddr specifies the internal address register 
00097    *         where to start writing to (must be correctly masked).
00098    * @param  NumByteToWrite number of bytes to be written.
00099    * @retval 0 if ok, 
00100    * @retval -1 if an I2C error has occured, or
00101    * @retval -2 on temporary buffer overflow (i.e. NumByteToWrite was too high)
00102    * @note   On some devices if NumByteToWrite is greater
00103    *         than one, the RegisterAddr must be masked correctly!
00104    */
00105    int i2c_write(uint8_t* pBuffer, uint8_t DeviceAddr, uint16_t RegisterAddr, 
00106                  uint16_t NumByteToWrite)
00107    {
00108      int ret;
00109      uint8_t tmp[TEMP_BUF_SIZE];
00110      
00111      if(NumByteToWrite >= TEMP_BUF_SIZE) return -2;
00112      
00113      /* First, send device address. Then, send data and STOP condition */
00114      tmp[0] = (RegisterAddr >> 8) & 0xFF;
00115      tmp[1] = (RegisterAddr) & 0xFF;
00116      memcpy(tmp+2, pBuffer, NumByteToWrite);
00117      
00118      ret = write(DeviceAddr, (const char*)tmp, NumByteToWrite+2, false);
00119      
00120      if(ret) return -1;
00121      return 0;
00122    }
00123    /**
00124    * @brief  Reads a buffer from the I2C peripheral device.
00125    * @param  pBuffer pointer to the byte-array to read data in to
00126    * @param  DaviceAddr specifies the peripheral device slave address.
00127    * @param  RegisterAddr specifies the internal address register 
00128    *         where to start reading from (must be correctly masked).
00129    * @param  NumByteToRead number of bytes to be read.
00130    * @retval 0 if ok, 
00131    * @retval -1 if an I2C error has occured
00132    * @note   On some devices if NumByteToWrite is greater
00133    *         than one, the RegisterAddr must be masked correctly!
00134    */
00135    int i2c_read(uint8_t* pBuffer, uint8_t DeviceAddr, uint16_t RegisterAddr, 
00136                 uint16_t NumByteToRead)
00137    {
00138      int ret;
00139      uint8_t reg_addr[2];
00140      reg_addr[0] = (RegisterAddr >> 8) & 0xFF;
00141      reg_addr[1] = (RegisterAddr) & 0xFF;
00142      /* Send device address, with no STOP condition */
00143      ret = write(DeviceAddr, (const char*)reg_addr, 2, true);
00144      if(!ret) {
00145        /* Read data, with STOP condition  */
00146        ret = read(DeviceAddr, (char*)pBuffer, NumByteToRead, false);
00147      }
00148      
00149      if(ret) 
00150        return -1;
00151      else
00152        return 0;
00153    }
00154    
00155    /**
00156    * @brief  Reads a buffer from the I2C peripheral device.
00157    * @param  pBuffer pointer to the byte-array to read data in to
00158    * @param  DaviceAddr specifies the peripheral device slave address.
00159    * @param  RegisterAddr specifies the internal address register 
00160    *         where to start reading from (must be correctly masked).
00161    * @param  NumByteToRead number of bytes to be read.
00162    * @retval 0 if ok, 
00163    * @retval -1 if an I2C error has occured
00164    * @note   On some devices if NumByteToWrite is greater
00165    *         than one, the RegisterAddr must be masked correctly!
00166    */
00167    int i2c_read(uint8_t* pBuffer, uint8_t DeviceAddr, uint8_t RegisterAddr, 
00168                 uint16_t NumByteToRead)
00169    {
00170      int ret;
00171      
00172      /* Send device address, with no STOP condition */
00173      ret = write(DeviceAddr, (const char*)&RegisterAddr, 1, true);
00174      if(!ret) {
00175        /* Read data, with STOP condition  */
00176        ret = read(DeviceAddr, (char*)pBuffer, NumByteToRead, false);
00177      }
00178      
00179      if(ret) return -1;
00180      return 0;
00181    }
00182    
00183 private:
00184   static const unsigned int TEMP_BUF_SIZE = 32;
00185 };
00186 
00187 #endif /* __DEV_I2C_H */