M29W800DT-70N6

The M29W800DT-70N6 is an 8 megabit 3V dual-organization top-boot NOR Flash memory from STMicroelectronics. The ‘DT’ designation indicates dual (x8/x16) organization with top boot block architecture — the boot and parameter blocks are located at the highest (top) address range, as opposed to bottom boot devices where they are at the lowest addresses. This top boot configuration is preferred by certain processor architectures (e.g., PowerPC, MIPS, some ARM implementations) that start code execution from the upper address range after power-on reset. The device can be configured as 512K words of 16 bits (x16 mode, BYTE# high) or 1M bytes of 8 bits (x8 mode, BYTE# low), providing design flexibility for different bus widths. The block organization consists of fifteen 64KB main blocks, one 32KB block, two 8KB parameter blocks, and one 16KB boot block — all at the top of the address map. With 70ns access time, it supports fast execute-in-place (XIP) operation. The device operates from a single 2.7V to 3.6V supply for all operations, with on-chip charge pumps generating program and erase voltages. Advanced features include Write to Buffer, Program/Erase Suspend/Resume, status register monitoring, and hardware block protection. Packaged in a 48-pin TSOP Type N surface-mount package and fully specified for -40°C to +85°C industrial operation, the M29W800DT-70N6 is ideal for PowerPC-based systems, networking equipment, industrial controllers, and high-end embedded applications requiring top boot Flash memory.

The M29W800DT is a top-boot dual-organization NOR Flash memory. The ‘top boot’ architecture means the boot block (containing system initialization code) and parameter blocks are located at the highest addresses in the memory map, rather than at the bottom (lowest addresses). This is important because different processor architectures have different reset vector locations — some start executing at address 0 (bottom boot), while others start at the top of the address space (top boot). PowerPC, MIPS, and many 32-bit RISC processors typically use top boot address maps. The dual organization (x8/x16) allows the same memory chip to interface with either 8-bit or 16-bit data buses, selected by the BYTE# pin. In x16 mode, 16 data bits are read/written per access; in x8 mode, only 8 bits are used, with the A-1 address pin selecting which byte of each 16-bit word is accessed. NOR Flash provides random read access — applying an address latches data on the output pins after the 70ns access time. This enables execute-in-place (XIP) operation where the processor fetches instructions directly from Flash without needing to copy code to RAM first. Program and erase operations are initiated by writing command sequences to the device. The internal state machine then handles the operation automatically. Write to Buffer allows loading up to 32 words/bytes into a buffer before programming, which is much faster than programming each location individually. Program/Erase Suspend allows pausing an operation to perform reads in other blocks, then resuming. This is valuable for systems that need periodic access to Flash data even during firmware updates. Block protection can lock specified blocks (typically the boot block) to prevent accidental erasure or programming, ensuring the system can always boot even if something goes wrong during firmware update.

• PowerPC and RISC processor systems
• Network routers and switches
• Telecom base station controllers
• Industrial PLC and CNC systems
• High-performance embedded systems
• Automotive control units
• Medical imaging equipment
• Aerospace and defense electronics