Consumer electronics are using memory to store information and to transmit the same. The EEPROM memory is one of the popular memory types. In this article, we discuss the workings of AT24CM02-SSHM-B, one of the popular EEPROM memories from Integrated Circuit (IC) manufacturer, Microchip Technology.
How Does an EEPROM Memory Work?
EEPROM is a format of semiconductor device, optimized for storing information/data on the Integrated Circuit (IC). It is a non-volatile memory designed to process data transfer via the I2C memory interface.
AT24CM02-SSHM-B’s Writing Operations and Error Detection Capabilities
Error detection is now an integral component or feature in most Integrated Circuits (ICs). AT24CM02-SSHM-B is not lagging in that respect, either. The built-in error detection capabilities interface with the writing operations.
First, let us talk about the writing operations. AT24CM02-SSHM-B uses a Start Condition, which the host uses to initiate a data transfer sequence. Upon the activation of the said condition, it would then be up to the built-in Error Detection and Correction (EDC) logic scheme to find the “faults.”
The EDC logic scheme then reads the 38-bit of Error Correction Codes (ECCs) in the EEPROM Array. By reading these codes, the EDC finds out if there is anything out of place by comparing the 6 ECC bits from the EEPROM with the four connected 8-bit bytes from the EEPROM Array.
The comparison reveals whether there has been any incorrect reading of any of the bytes from either section (the EEPROM Array and the EEPROM).
In the case of an incorrect data reading, what the Error Detection and Correction (EDC) logic does is to use a correct or updated value to replace the incorrect bit. That way, everything relating to the data would be uniform by the time it is serially clocked out.
AT24CM02-SSHM-B has Higher Data Reliability
Everything relating to data must not be treated with kid’s gloves, especially when it is used in consumer electronics. Microchip Technology, the manufacturer of AT24CM02-SSHM-B’s EEPROM Memory function takes that into consideration.
It maintains the highest data reliability standards by first using the endurance rating up to 1 million write cycles. It also keeps the data or information safe with the 100-year data retention.
AT24CM02-SSHM-B Attributes
The table below shows the different values making up the AT24CM02-SSHM-B EEPROM Memory:
| Attributes | Description |
| Operating Temperature (minimum to maximum) | 40-degree Celsius to 85-degree Celsius |
| Type of Memory | Non-volatile |
| Type of Package | Tube |
| Type of Case | 8-SOIC |
| Technology Used | EEPROM |
| Clock Frequency | 1 MHz |
| Memory Format | EEPROM |
| Voltage Supply (minimum to maximum) | Between 1.7 volts and 5.5 volts |
| Memory Interface | I2C |
| Estimated Write Cycle Time | 10ms |
| Access Time | 450 nanoseconds (ns) |
AT24CM02-SSHM-B Pin Considerations
Pins play an essential role in the functions of an Integrated Circuit (IC). Careful considerations are to be made when working with these pins. AT24CM02-SSHM-B’s pins are important elements in the data writing capabilities.
Up to eight (8) different pins are supported, namely:
- VCC
- NC
- WP
- A2
- SCL
- GND
- SDA
These pins cut across different ball compositions and functions, such as:
- Device power supply
- No connect
- Ground
- Write-protect
- Device address input
- Serial clock
- Serial data
The SDA and SCL Pins: What’s the Difference?
The Serial Clock (SCL) and the Serial Data (SDA) pins appear to share the same function, but there is a thin line differentiating one from the other.
On the one hand, SDA is an open-drain bidirectional Input and Output (I/O) pin meant to make serial transfer or movement of data to and from the (target) device.
On the other hand, the Serial Clock (SCL) provides a clock to the (target) device. The clock helps regulate the movement, transfer or flow of data to and from the (target) device.
Thus, the difference between the two is that despite aiding data transfer to and from the target device, the SDA differentiates from the SCL because it is an Input and Output (I/O) pin, while the latter provides a clock for the data transfer.
Device Address Input (A2)
This type of pin is used primarily for connecting two or more Serial EEPROM devices. For that to work, the Device Address Input (A2) is first hard-wired either to the VCC or to the GND pins.
Either way, the hard-wiring paves the way for the creation of compatible interfacing between the GND or the VCC pins with the additional two-wire Serial EEPROM devices. That way, multiple devices can be addressed or connected via a serial bus system.
Write-Protect (WP)
The Write-Protect or WP pin is used to enable the normal writing operations in the AT24CM02-SSHM-B EEPROM memory.
For the writing to be enabled, AT24CM02-SSHM-B is first connected to the Ground (GND) pin.
However, it provides protection for the data in the form of prohibited access. To enable this, the Write-Protect (WP) is connected directly to the Device Power Supply or VCC pin. By making this direct connection, Write-Protect (WP) prevents the memory from exposure, especially for the write operations.
How the VCC and the GND Pins Work in AT24CM02-SSHM-B
The remaining pins to analyze are the Ground (GND) and the Device Power Supply (VCC) pins.
They work together in the sense that the VCC is the major supply voltage to the device, while the GND serves as the “ground reference for the power supply.”
The Data Transfer Process
Data transfer is done via AT24CM02-SSHM-B’s I2C-compatible two-wire digital serial interface. Through this interface, the memory communicates or interfaces with the host controller. For emphasis, the host controller is the core initiator and manager of the client devices’ read and write operations.
It also oversees the enablement of the two-way data transfer process, allowing the client devices and the host (bus host) to transfer and receive data on the same bus.
The data transfer process typically involves the reception of the clock from the host through the Serial Clock (SCL). Once this has been done, the next stage would be the reception and transfer of the data information and command from the Serial Data (SDA) pin.
Conclusion
AT24CM02-SSHM-B is an excellent EEPROM memory required for surface-mounted devices needing excellent command and data transfer to and from the target devices/circuit boards.
