ReRAM 2 Click

How does it work?

ReRAM 2 Click as its foundation uses the MB85AS8MT, a highly reliable 8Mbit resistive random-access memory (ReRAM) organized as 1,048,576 words of 8 bits from Fujitsu Semiconductor. It uses the resistance-variable memory process and silicon-gate CMOS process technologies to form nonvolatile memory cells. The MB85AS8MT specifies 1.000.000 endurance cycles with data retention of a minimum of 10 years, which gives the MB85AS8MT the capability to handle unlimited reads/writes to the memory.

One prominent feature of the MB85AS8MT is an extremely small average current, despite its large density, for reading operations of 0.15mA at an operating frequency of 5MHz, which is only 5% of large density EEPROM devices. This feature enables minimal power consumption when in applications with frequent data-read operations. Besides higher write endurance, it has faster write speeds than EEPROM and flash memory, while its electric specifications, such as commands and timings, are compatible with EEPROM products.

The ReRAM 2 Click communicates with MCU through a standard SPI interface that enables high clock speeds up to 10MHz, supporting the two most common SPI modes, SPI Mode 0 and 3. An additional feature of this Click board™ represents the configurable Write Protection function labeled as WP routed on the PWM pin of the mikroBUS™ socket. The WP pin protects the entire memory and all registers from write operations and must be set to a low logic state to inhibit all the write operations. All memory and register writes are prohibited when this pin is low, and the address counter is not incremented. Besides, the ReRAM 2 Click also has an additional HOLD pin, routed to the RST pin of the mikroBUS™ socket labeled as HO, to interrupt a serial operation without aborting it.

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. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

Specifications

Pinout diagram

This table shows how the pinout on ReRAM 2 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	WP	Write Protection
SPI Suspension	HO	2	RST	INT	15	NC
SPI Chip Select	CS	3	CS	RX	14	NC
SPI Clock	SCK	4	SCK	TX	13	NC
SPI Data OUT	SDO	5	MISO	SCL	12	NC
SPI Data IN	SDI	6	MOSI	SDA	11	NC
Power Supply	3.3V	7	3.3V	5V	10	NC
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

ReRAM 2 Click electrical specifications

Software Support

We provide a library for the ReRAM 2 Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for ReRAM 2 Click driver.

Key functions

• reram2_read_device_id ReRAM 2 read device ID function.

• reram2_write_memory ReRAM 2 write memory function.

• reram2_read_memory ReRAM 2 read memory function.

Example Description

This library contains API for ReRAM 2 Click driver.

 void application_task ( void ) 
 { 
     static char rx_data[ 9 ] = { 0 }; 

     reram2_read_memory( &reram2, memory_addr, &rx_data[ 0 ], 9 ); 
     log_printf( &logger, "  Read data  : %s", rx_data );  
     log_printf( &logger, "-----------------------rn" ); 
     Delay_ms( 2000 ); 
 }

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.ReRAM2

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MikroElektronika compilers.

mikroSDK

This Click board™ is supported with mikroSDK – MikroElektronika Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.