DS5001FP
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DESCRIPTION
The DS5001FP 128k soft microprocessor chip is an 8051-compatible microprocessor based on NV RAM
technology and designed for systems that need large quantities of nonvolatile memory. It provides full
compatibility with the 8051 instruction set, timers, serial port, and parallel I/O ports. By using NV RAM
instead of ROM, the user can program and then reprogram the microprocessor while in-system. The
application software can even change its own operation, which allows frequent software upgrades,
adaptive programs, customized systems, etc. In addition, by using NV SRAM, the DS5001FP is ideal for
data logging applications. It also connects easily to a Dallas real-time clock.
The DS5001FP provides the benefits of NV RAM without using I/O resources. It uses a nonmultiplexed
byte-wide address and data bus for memory access. This bus performs all memory access and provides
decoded chip enables for SRAM, which leaves the 32 I/O port pins free for application use. The
DS5001FP uses ordinary SRAM and battery-backs the memory contents for over 10 years at room
temperature with a small external battery. A DS5001FP also provides high-reliability operation in harsh
environments. These features include the ability to save the operating state, power-fail reset, power-fail
interrupt, and watchdog timer.
A user programs the DS5001FP through its on-chip serial bootstrap loader. The bootstrap loader
supervises the loading of software into NV RAM, validates it, and then becomes transparent to the user.
Software can be stored in multiple 32kB or one 128kB CMOS SRAM(s). Using its internal partitioning,
the DS5001FP can divide a common RAM into user-selectable program and data segments. This partition
can be selected at program loading time, but can then be modified later at any time. The microprocessor
decodes memory access to the SRAM and addresses memory through its byte-wide bus. Memory portions
designated code or ROM are automatically write-protected by the microprocessor. Combining program
and data storage in one device saves board space and cost.
The DS5001FP offers several bank switches for access to even more memory. In addition to the primary
data area of 64kB, a peripheral selector creates a second 64kB data space with four accompanying chip
enables. This area can be used for memory-mapped peripherals or more data storage. The DS5001FP can
also use its expanded bus on ports 0 and 2 (like an 8051) to access an additional 64kB of data space.
Lastly, the DS5001FP provides one additional bank switch that changes up to 60kB of the NV RAM
program space into data memory. Thus, with a small amount of logic, the DS5001 accesses up to 252kB
of data memory.
The DS2251T is available (Refer to the data sheet at www.maxim-ic.com/microcontrollers.) for users
who want a preconstructed module using the DS5001FP, RAM, lithium cell, and a real-time clock. For
more details, refer to the Secure Microcontroller User’s Guide. For users desiring software security, the
DS5002FP is functionally identical to the DS5001FP but provides superior firmware security. The 44-pin
version of the device is functionally identical to the 80-pin version but sports a reduced pin count and
footprint.
Refer to the Secure Microcontroller User’s Guide for operating details. This data sheet provides ordering
information, pinout, and electrical specifications.
ORDERING INFORMATION
PART PIN-PACKAGE MAX. CLOCK SPEED (MHz) TEMP. RANGE (°C)
DS5001FP-16 80-MQFP 16 0 to +70
DS5001FP-16N 80-MQFP 16 -40 to +85
DS5001FP-12-44 44-MQFP 12 0 to +70