Intel JS28F256P30B95: A Comprehensive Technical Overview of the 256-Megabit P30 Parallel NOR Flash Memory
The Intel JS28F256P30B95 represents a specific implementation within Intel's (now Micron's) renowned P30 family of parallel NOR Flash memory devices. This 256-megabit (32-megabyte) component is engineered for high-performance, reliable non-volatile storage in a wide array of embedded systems, ranging from networking equipment and telecommunications infrastructure to industrial automation and avionics. Its parallel interface and advanced architecture make it a cornerstone for applications requiring fast read access, instant-on execution, and robust data integrity.
Architecture and Core Technology
Fabricated on industry-leading 90nm StrataFlash® Cellular Memory (P30) technology, this device organizes its 256Mb density as a uniform sector architecture, typically configured as 128 uniform 256-Kbyte sectors. This structure provides exceptional flexibility for code and data storage, allowing individual sectors to be erased, programmed, or locked independently. The core innovation of the P30 technology lies in its multi-level cell (MLC) design, which stores two bits of data per memory cell. This approach effectively doubles the density compared to single-level cell (SLC) NOR Flash without a proportional increase in die size, offering a compelling balance of cost, capacity, and performance.
Performance and Interface
A defining characteristic of the JS28F256P30B95 is its high-speed asynchronous page-mode read capability. It features a 16-bit wide data bus and supports a page size of 8 words (16 bytes). This allows for extremely fast read operations, with initial access times as low as 90ns and subsequent page accesses as fast as 25ns. This performance is critical for systems that execute code directly from Flash (XiP - eXecute in Place), minimizing wait states for the host processor and boosting overall system efficiency. The device operates across a standard 2.7V to 3.6V voltage range, making it suitable for a broad spectrum of 3V system designs.
Advanced Features for System Reliability
Beyond raw storage, this memory integrates several features to enhance system security and data integrity. It includes a hardware-assisted write protection scheme that utilizes a dedicated WP (Write Protect) pin to prevent accidental modification of the memory contents. Furthermore, it offers 64 OTP (One-Time Programmable) registers. These secure, lockable bytes are often used to store sensitive data like encryption keys, device serial numbers, or final configuration settings. For robust operation in electrically noisy environments, the device incorporates advanced error correction code (ECC) logic, capable of detecting and correcting single-bit errors, thereby significantly improving data retention and endurance.
Programming and In-System Management
The JS28F256P30B95 supports efficient in-system updates. It complies with the Common Flash Memory Interface (CFI), which allows host software to automatically query the device to determine its architecture, electrical characteristics, and command set. This simplifies driver development and system integration. Programming and erase functions are executed through a standardized command sequence written to the device's command register. The chip features a buffered programming mode that significantly accelerates the write process by allowing a continuous write of an entire data buffer (e.g., 32 words) without the need for the software to wait for each word to complete, thereby reducing overall system write time.
Target Applications and Longevity
This memory is purpose-built for demanding embedded applications. Its primary use cases include:
Networking & Communications: Storing boot code, firmware, and operating systems in routers, switches, and base stations.
Industrial Control Systems: Providing reliable storage for program logic in PLCs, motor drives, and robotic controllers.
Aerospace and Defense: Serving in systems that require extreme reliability, long-term life cycles, and radiation tolerance.
Automotive: Used in pre-boot environments and critical electronic control units (ECUs) requiring fast, deterministic read access.
As a component designed for the embedded market, it is characterized by its extended longevity and availability, ensuring support for the long life cycles typical of these industries.
ICGOOODFIND
The Intel JS28F256P30B95 is a high-density, high-performance parallel NOR Flash memory solution that masterfully balances speed, reliability, and cost-effectiveness. Its advanced 90nm P30 MLC technology, fast page-mode reads, and comprehensive suite of security and reliability features make it an enduring and trusted choice for mission-critical embedded systems where data integrity and instant-on execution are non-negotiable requirements.
Keywords:
1. Parallel NOR Flash
2. Execute-in-Place (XiP)
3. 90nm StrataFlash® P30
4. Asynchronous Page-Mode Read
5. Error Correction Code (ECC)
