Intel RC28F128P30T85: A Deep Dive into the 128-Megabit Parallel Block Erase Flash Memory
The Intel RC28F128P30T85 stands as a significant milestone in the evolution of non-volatile memory, representing a high-performance, 128-megabit (16-megabyte) flash memory component designed for demanding embedded systems. This device, built on a mature yet highly effective parallel interface architecture, was engineered to deliver reliability and speed for applications ranging from telecommunications infrastructure to industrial control systems.
At its core, the chip is organized as 128 megabits, configured as 8,192 erasable sectors (or blocks) of 16 Kbytes each. This fine-grained block architecture is a critical feature, allowing system software to erase and rewrite specific segments of data without affecting the entire memory array. This minimizes overhead and significantly enhances efficiency compared to full-chip erase operations. The asymmetrical block structure, with a main array and smaller parameter blocks, offers flexibility for storing both large application code and smaller, frequently updated configuration data.
A defining characteristic of this memory is its parallel interface with a multiplexed address and data bus. This 56-pin TSOP package uses a 16-bit data bus and 25 address lines (A0-A24) to access its entire memory space. While modern systems have largely shifted to serial interfaces for higher density and simpler routing, this parallel approach offers a distinct advantage: raw, low-latency read performance. By outputting data on a wide bus directly controlled by address lines, it enables near-instantaneous access, which is crucial for execute-in-place (XIP) operations where the CPU fetches code directly from the flash.
The "P30" in its nomenclature highlights its access speed. With a fast 85ns maximum access time, the RC28F128P30T85 could keep pace with high-performance microprocessors of its era without introducing significant wait states. The device also incorporates advanced functionality for its time, including a write state machine that automates the program and erase algorithms, reducing the burden on the host processor. Furthermore, it features a hardware-based write protection scheme. By asserting the `RP` (Reset/Power-Down) pin, the entire memory array is protected from accidental program or erase cycles, a vital safeguard for system integrity during power transitions or in noisy environments.
Despite being based on older technology, its legacy lies in its robustness. It offered one million erase/program cycles per sector and a data retention capability of up to 20 years, specifications that made it a trusted choice for mission-critical applications where failure was not an option.
ICGOOODFIND: The Intel RC28F128P30T85 is a quintessential example of high-performance parallel NOR flash memory. Its combination of a fast 85ns access time, a flexible 16-Kbyte block erase architecture, and robust hardware protection features made it an ideal solution for embedded systems requiring reliable, low-latency code storage and execution. It embodies an era of design where performance and reliability were achieved through a wide, parallel interface and intelligent memory management.
Keywords: Parallel NOR Flash, Block Erase Architecture, Execute-in-Place (XIP), 85ns Access Time, Hardware Write Protection
