AT28C64-12PC

Memory: AT28C64-12PC Application Fields and Working Principles

AT28C64-12PC is a member of Atmel\'s series of 64K EEPROMs. It is a non-volatile memory device, especially designed for high speed, low voltage, battery back-up, high density and low power applications. It is designed for flexibility, as it can be used for various data and code storage, memory mirroring and programmable read/write access. This article will provide an overview of the various application fields in which the AT28C64-12PC can be used, and will discuss the working principles of this device.

Application Fields

The AT28C64-12PC is a general-purpose RAM, appropriate for a range of applications, especially those provided low power, low speed and low voltage:

• Data Storage and Transfer – The AT28C64-12PC is an ideal choice for general-purpose data and code storage, allowing for quick and easy programming of up to 32K bytes of data. It is also suitable for high-speed data transfer, allowing for fast and efficient transfer of data to and from devices with limited access times.
• Memory Mirroring – The AT28C64-12PC also support memory mirroring, which allows multiple memory banks to share the same memory address space. This makes it suitable for embedded systems and applications requiring multiple memory banks for redundant storage.
• Programmable Read/Write Access – The AT28C64-12PC can be programmed for read/write access through the pin array interface, allowing for flexible and cost-effective memory management.

Working Principles

The AT28C64-12PC works by using eight active pins for data transfer, four of which are data input pins and four are data output pins. Data can be stored and retrieved via the active pins via a register called the Data Input Register. Data that is written to the Data Input Register is then transferred to the EEPROM\'s internal memory via the chip\'s write circuit. Data stored in the memory can then be accessed by similar read operation, which transfers the data from the EEPROM\'s memory back to the Data Input Register.

In addition to the active pins, the AT28C64-12PC also has four other pins: the Chip Enable (CE), Output Enable (OE), Address Latch Enable (ALE), and Write Enable (WE) pins. The CE pin is used to activate the device; when it is pulled low, the chip\'s circuitry is enabled and the device can be read from or written to. The OE pin controls the Data Input Register, and can be used to set the device in either a read or write mode. The ALE pin is used to latch the address to be accessed, and the WE pin controls the write/read operation.

When activating the device, the OE pin is first set to low. This causes the Data Input Register to be enabled, and the EEPROM\'s contents can be read from or written to. The ALE and WE pins are then both set to high for a brief period of time. This latches the address and activates the device, depending on whether the WE pin is set to high or low (to initiate a write operation or read operation, respectively). The AT28C64-12PC then performs the corresponding operation on the data located at the specified address, and then sets the OE pin back to low.

Conclusion

The AT28C64-12PC is a versatile memory chip that is suitable for a wide range of applications. It can be used for data storage, data transfer, and memory mirroring, and can be programmed to provide flexible read/write access. It works by transferring data between its internal memory and the Data Input Register via its active data pins, and uses its CE, OE, ALE and WE pins to control the read/write operation.