Maximize data storage capacity with AT24CM02 and ATmega644
4 million reasons to choose EEPROM!
Published Aug 23, 2023
Click board™
Dual EE Click
Dev Board
EasyAVR v7
Compiler
NECTO Studio
MCU
ATmega644
Amplify your data storage prowess through our state-of-the-art solution, showcasing dual EEPROM memory with an impressive 4Mb capacity
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Hardware Overview
How does it work?
Dual EE Click is based on two AT24CM02, an I2C serial EEPROM from Microchip. This means the ICs can have a different I2C address so that users can choose which one they would like to use at a particular time. This is achieved by wiring the I2C address selection lines from one of the ICs to the VCC while the other IC is wired to the GND. Given this feature, it is important to note that this click board has 4MB of memory. This Click board™ uses the I2C communication protocol. Therefore, the host MCU initiates every data transaction event, transmitting the I2C START condition, followed by the AT24CM02 device ID byte. Upon receiving the device ID byte, the AT24CM02 IC expects two more address bytes, completing the 18-bit address word. The EEPROM density is usually expressed in bits, so exactly 2.097.152 bits are organized in units or words of 8 bits, which gives 262.144 bytes of data memory. Furthermore, the EEPROM is
organized into so-called pages. One page holds 256 bytes, and there are 1024 pages (1024 pages x 256 bytes = 262.144 bytes total). Given that this click contains two EEPROM Ics, this Click board™ has twice as much memory, equaling 4 MB. Having insight into how the memory cells are organized is important for Write and Erase operations. The I2C pins are routed to the mikroBUS™, making communication easy and straightforward. Both 100KHz and 400KHz transfer speeds are supported by the AT24CM02 IC and the 1MHz Fast Mode Plus (FM+) I2C communication for the MCUs with I2C modules that can support that speed. One of the key features of the AT24CM02 IC is the Error Detection and Correction scheme (EDC), which allows error correction by utilizing six additional bits internally assigned to a group of four bytes. This protection scheme can correct some bit errors, staying transparent to the end
user. The bit comparison and error correction are done internally. The Dual EE Click board™ offers a selection between 3.3V and 5V operation, with the onboard SMD jumper labeled PWR SEL. This allows both 3.3V and 5V MCUs to be interfaced with this Click board™. The attached device datasheet contains an in-depth explanation of all the mentioned functions. However, Mikroe provides a library with functions that make the final code clean and readable, simplifying working with this device. These functions internally employ the aforementioned communication mechanism and expose only a simple and clean interface to the user. The provided example code demonstrates the functionality of these functions. It can be used as a reference point for custom development.
Features overview
Development board
EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more
efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)
connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
64
Silicon Vendor
Microchip
Pin count
40
RAM (Bytes)
4096
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the EasyAVR v7 as your development board.
Track your results in real time
Application Output
1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.
2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.
3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.
Software Support
Library Description
This library contains API for Dual EE Click driver.
Key functions:
dualee_read- Generic write data functiondualee_write- Generic write data function
Open Source
Code example
The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.
/*!
* \file
* \brief DualEE Click example
*
* # Description
* This application writes data in memory and reads data from memory
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes device init
*
* ## Application Task
* Reads your command and then execute it
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "dualee.h"
// ------------------------------------------------------------------ VARIABLES
static dualee_t dualee;
static log_t logger;
static uint32_t page_address = 0x00000000;
static uint8_t write_data[ 7 ] = { 'M', 'i', 'k', 'r', 'o', 'E', 0 };
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
dualee_cfg_t cfg;
/**
* Logger initialization.
* Default baud rate: 115200
* Default log level: LOG_LEVEL_DEBUG
* @note If USB_UART_RX and USB_UART_TX
* are defined as HAL_PIN_NC, you will
* need to define them manually for log to work.
* See @b LOG_MAP_USB_UART macro definition for detailed explanation.
*/
LOG_MAP_USB_UART( log_cfg );
log_init( &logger, &log_cfg );
log_info( &logger, "---- Application Init ----" );
// Click initialization.
dualee_cfg_setup( &cfg );
DUALEE_MAP_MIKROBUS( cfg, MIKROBUS_1 );
dualee_init( &dualee, &cfg );
log_printf( &logger, "*********** APPLICATION INIT ***********\r\n" );
Delay_ms( 100 );
}
void application_task ( )
{
uint8_t write_dual;
uint8_t read_dual;
char demo_text[ 255 ];
log_printf( &logger, "Writing data [MikroE]....\r\n" );
write_dual = dualee_write( &dualee, page_address, write_data, 7 );
if ( write_dual == DUALEE_ERROR_RW )
{
log_printf( &logger, "Error writing data!!!\r\n" );
Delay_ms( 1000 );
return;
}
Delay_ms( 100 );
log_printf( &logger, "Reading data...\r\n" );
read_dual = dualee_read( &dualee, page_address, demo_text, 7 );
if ( read_dual == 0 )
{
log_printf( &logger, "Error reading data!!!\r\n" );
Delay_ms( 1000 );
return;
}
Delay_ms( 100 );
log_printf( &logger, "Data from read page is: %s \r\n", demo_text );
log_printf( &logger, "__________________________________\r\n" );
Delay_ms( 1000 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
