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# 1.39 TWIHS EEPROM Read Write

This example shows how to use the TWIHS peripheral to write and read from the I2C serial EEPROM memory.

## Description

This example uses the TWIHS peripheral library to write an array of values to the I2C Serial EEPROM and verify the value written by reading the values back and comparing it to the value written.

## Downloading and Building the Application

To clone or download this application from Github, go to the main page of this repository and then click Clone button to clone this repository or download as zip file. This content can also be downloaded using content manager by following these instructions.

Path of the application within the repository is apps/twihs/master/twihs_eeprom/firmware.

To build the application, refer to the following table and open the project using its IDE.

Project Name | Description
--- | ---
pic32cz_ca70_curiosity_ultra.X | MPLABX project for PIC32CZ CA70 Curiosity Ultra Development Kit

## Setting Up the Hardware

The following table shows the target hardware for the application projects.

Project Name | Description
--- | ---
pic32cz_ca70_curiosity_ultra.X | PIC32CZ CA70 Curiosity Ultra Development Kit

### Setting Up PIC32CZ CA70 Ultra Curiosity Development Kit

- Connect the Debug USB port on the board to the computer using a micro USB cable
- If this application is used for communicating with apps/twihs/slave/i2c_eeprom_emulation application, then connect TWIHS SDA line on Pin 11 (PA03) of EXT1 connector and TWIHS SCL line on Pin 12 (PA04) of EXT1 connector with the corresponding SDA and SCL lines of the TWIHS client

## Running the Application

1. Open the main.c file and make sure the following macro is defined to true when communicating with on-board EEPROM and to false when communicating with the apps/twihs/slave/i2c_eeprom_emulation application.
   When communicating with on-board EEPROM:

       #define I2C_SLAVE_IS_ONBOARD_EEPROM           true

   When communicating with apps/twihs/slave/i2c_eeprom_emulation application

       #define I2C_SLAVE_IS_ONBOARD_EEPROM           false

2. Build and Program the application using its IDE
3. The LED indicates the success or failure:
   - The LED is turned ON when the value read from the EEPROM matched with the written value
   - The LED is turned OFF when the value read from the EEPROM did not match with the written value

Refer to the following table for LED names:

Board | LED Name
--- | ---
PIC32CZ CA70 Curiosity Ultra Development Kit | LED0