STM32F0xx Standard Peripherals Firmware Library: How to use the I2C to drive an EEPROM memory

STM32F0xx Standard Peripherals Library

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How to use the I2C to drive an EEPROM memory 
  ******************** (C) COPYRIGHT 2014 STMicroelectronics *******************
  * @file    I2C/I2C_EEPROM/readme.txt 
  * @author  MCD Application Team
  * @version V1.4.0
  * @date    24-July-2014
  * @brief   Description of the I2C and M24Lxx EEPROM communication example.
  ******************************************************************************
  *
  * Licensed under MCD-ST Liberty SW License Agreement V2, (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.st.com/software_license_agreement_liberty_v2
  *
  * 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.
  *
  ******************************************************************************
Example Description

This firmware provides a basic example of how to use the I2C firmware library and an associate I2C EEPROM driver to communicate with an I2C EEPROM device (here the example is interfacing with M24LR64 EEPROM)

I2C peripheral is configured in Master transmitter during write operation and in Master receiver during read operation from I2C EEPROM.

The peripheral used is I2C1 but can be configured by modifying the defines values in stm320518_eval.h or stm32072b_eval.h file. The maximum speed of communication with M24LR64 is 400kHz. The speed of communication is configured by setting the value of sEE_I2C_TIMING define in stm320518_eval_i2c_ee.h or stm32072b_eval_i2c_ee.h file.

For M24LR64 devices all the memory is accessible through the two-bytes addressing mode and need to define block addresses. In this case, the physical address has to be defined according to the address pins (E1, E2) connection.

This address is defined in stm320518_eval_i2c_ee.h or in stm32072b_eval_i2c_ee.h. The EEPROM addresses where the program start the write and the read operations is defined in the main.c file.

First, the content of Tx1Buffer is written to the sEE_WRITE_ADDRESS1 and the written data are read. The written and the read buffers data are then compared. Following the read operation, the program waits that the EEPROM reverts to its Standby state. A second write operation is, then, performed and this time, Tx2Buffer is written to sEE_WRITE_ADDRESS2, which represents the address just after the last written one in the first write. After completion of the second write operation, the written data are read. The contents of the written and the read buffers are compared.

All transfers are managed in Polling mode by calling sEE_ReadBuffer() or sEE_WriteBuffer() function.

User should refer to stm320518_eval.h or to stm32072b_eval.h file to select which EEPROM use in this example.

This example provides the possibility to use the LCD screen for messages display (transfer status: PASSED, FAILED). To enable this option uncomment the define ENABLE_LCD_MSG_DISPLAY in the main.c file.

Directory contents
Note:
The "system_stm32f0xx.c" is generated by an automatic clock configuration tool and can be easily customized to meet user application requirements. To select different clock setup, use the "STM32F0xx_Clock_Configuration_VX.Y.Z.xls" provided with the AN4055 package available on ST Microcontrollers
Hardware and Software environment
  • This example runs on STM32F0xx devices.
  • This example has been tested with STMicroelectronics STM320518-EVAL and STM32072B-EVAL including respectively STM32F051R8T6 and STM32F072VBT6 devices and can be easily tailored to any other supported device and development board
  • STM320518-EVAL Set-up
    • When communicating with M24LR64 EEPROM, make sure that ANT7-M24LR is inserted in CN2 connector.
  • STM32072B-EVAL Set-up
    • When communicating with M24LR64 EEPROM, make sure that ANT7-M24LR is inserted in CN2 connector.
How to use it ?

In order to make the program work, you must do the following :

  • Copy all source files from this example folder to the template folder under Project
  • Open your preferred toolchain
  • If the used device is STM32F051R8T6 choose STM32F051 project
    • Add the following files to the project source list
      • Utilities/STM32_EVAL/STM320518_EVAL/stm320518_eval_i2c_ee.c
      • Utilities/STM32_EVAL/STM320518_EVAL/stm320518_eval.c
      • Utilities/STM32_EVAL/STM320518_EVAL/stm320518_eval_lcd.c
  • If the used device is STM32F072VBT6 choose STM32F072 project
    • Add the following files to the project source list
      • Utilities/STM32_EVAL/STM32072B_EVAL/stm32072b_eval_i2c_ee.c
      • Utilities/STM32_EVAL/STM32072B_EVAL/stm32072b_eval.c
      • Utilities/STM32_EVAL/STM32072B_EVAL/stm32072b_eval_lcd.c
  • Before building the project please make sure that "USE_DEFAULT_TIMEOUT_CALLBACK" define is removed from Preprocessor defines under C/C++ compiler settings.
  • Rebuild all files and load your image into target memory
  • Run the example

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