Capture and store critical information without constant power with 48LM01 and ATmega328
Serial EERAM memory for next-level data agility
Published Feb 14, 2024
Click board™
EERAM 2 Click
Dev Board
Arduino UNO Rev3
Compiler
NECTO Studio
MCU
ATmega328
Utilize serial EERAM in industrial machinery and automation systems, allowing quick recovery from power interruptions and ensuring minimal downtime and smooth operational continuity
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Hardware Overview
How does it work?
EERAM 2 Click is based on the 48LM01, a 1024-Kbit SRAM with EEPROM backup in each memory cell from Microchip. The user can treat this device as a full symmetrical read/write SRAM with no limits on cell usage. The device handles backup to EEPROM on any power disruption, so the user can effectively view this device as an SRAM that never loses its data. The SRAM is organized as 131,072 x 8 bits with access via the SPI serial interface. The backup EEPROM is invisible and cannot be accessed by the user independently. The 48LM01 includes circuitry that detects VCC dropping below a certain threshold, shuts its connection to the outside environment, and transfers all SRAM data to the EEPROM portion of each cell for safekeeping. When VCC returns, the circuitry automatically returns the data to the SRAM, and the user’s interaction with the SRAM can continue with the same data set. When power is first
applied to the click board™, the VCAP capacitor is charged to VCC through the 48LM01 IC. During normal SRAM operation, the capacitor remains charged, and the device monitors the level of system VCC. If the system VCC drops below a set threshold, the device interprets this as a power-off or brown-out event. The device suspends all I/O operation, shuts off its connection with the VCC pin, and uses the saved energy in the capacitor to power the device through the VCAP pin as it transfers all SRAM data to EEPROM. On the next power-up of VCC, the data is transferred back to SRAM, the capacitor is recharged, and the SRAM operation continues. Besides standard 4-wire SPI lines, 48LM01 has an additional HOLD pin. This pin can be used for transmission suspension to the 48LM01 while in the middle of a serial sequence without retransmitting the entire sequence. It must be held high any time this function is not
being used. Once the device is selected and a serial sequence is underway, the HOLD pin may be pulled low to pause further serial communication without resetting the serial sequence. The 48LM01 is internally organized as a continuous SRAM array for reading and writing, along with a non-volatile EEPROM array that is not directly accessible to the user but can be refreshed or recalled on power cycles or software commands. The SRAM array is continuously addressable, so the entire array can be written without accessing pages. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.
Features overview
Development board
Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an
ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the
first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
32
Silicon Vendor
Microchip
Pin count
32
RAM (Bytes)
2048
You complete me!
Accessories
Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
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 Arduino UNO Rev3 as your development board.
Track your results in real time
Application Output
This Click board can be interfaced and monitored in two ways:
Application Output- Use the "Application Output" window in Debug mode for real-time data monitoring. Set it up properly by following this tutorial.
UART Terminal- Monitor data via the UART Terminal using a USB to UART converter. For detailed instructions, check out this tutorial.
Software Support
Library Description
This library contains API for EERAM 2 Click driver.
Key functions:
eeram2_set_on_hold_status- Set On-hold status functioneeram2_set_command- Set command functioneeram2_set_write_status- Set write status 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 Eeram2 Click example
*
* # Description
* This example demonstrates the use of EERAM 2 click board.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and enables the click board.
*
* ## Application Task
* Writes a desired number of bytes to the memory and then verifies if it is written correctly
* by reading from the same memory location and displaying its content on the USB UART.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "eeram2.h"
// ------------------------------------------------------------------ VARIABLES
static eeram2_t eeram2;
static log_t logger;
static char demo_data[ 9 ] = { 'M', 'i', 'k', 'r', 'o', 'E', 13 ,10 , 0 };
static char read_data[ 9 ];
static uint8_t check_status;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
eeram2_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.
eeram2_cfg_setup( &cfg );
EERAM2_MAP_MIKROBUS( cfg, MIKROBUS_1 );
eeram2_init( &eeram2, &cfg );
eeram2_set_on_hold_status( &eeram2, EERAM2_HOLD_DISABLE );
Delay_ms( 100 );
eeram2_set_write_status( &eeram2, EERAM2_WRITE_ENABLE );
Delay_ms( 100 );
}
void application_task ( void )
{
check_status = eeram2_write_continuous( &eeram2, 0x00543210, &demo_data[ 0 ], 9 );
if ( check_status == EERAM2_ERROR )
{
log_printf( &logger, " ERROR Writing \r\n" );
log_printf( &logger, "--------------------\r\n" );
for ( ; ; );
}
log_printf( &logger, " Writing... \r\n" );
log_printf( &logger, "--------------------\r\n" );
Delay_ms( 100 );
check_status = eeram2_read_continuous( &eeram2, 0x00543210, &read_data[ 0 ], 9 );
if ( check_status == EERAM2_ERROR )
{
log_printf( &logger, " Reading ERROR \r\n" );
log_printf( &logger, "--------------------\r\n" );
for ( ; ; );
}
log_printf( &logger, " Read data : %s", read_data );
log_printf( &logger, "--------------------\r\n" );
Delay_ms( 1000 );
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
