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  1. 2009/01/03 DS5000FP - Soft Microprocessor Chip

DESCRIPTION
The DS5000FP Soft Microprocessor Chip is an 8051-compatible processor based on NV RAM
technology. It is substantially more flexible than a standard 8051, yet 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 microcontroller 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 DS5000FP is ideal for data-logging applications and it connects easily to a Dallas real-time clock for time stamp and date.
The DS5000FP provides the benefits of NV RAM without using I/O resources. It uses a non-multiplexed Byte-wide address and data bus for memory access. This bus can perform all memory access and provides decoded chip enables for SRAM. This leaves the 32 I/O port pins free for application use. The DS5000FP uses ordinary SRAM and battery backs the memory contents with a user’s external lithium cell. Data is maintained for over 10 years with a very small lithium cell. A DS5000FP also provides crashproof operation in portable systems or systems with unreliable power. These features include the ability to save the operating state, Power-fail Reset, Power-fail Interrupt, and Watchdog Timer.
A user loads programs into the DS5000FP via its on-chip Serial Bootstrap Loader. This function
supervises the loading of code into NV RAM, validates it, then becomes transparent to the user. Software can be stored in an 8-kbyte or 32-kbyte CMOS SRAM. Using its internal Partitioning, the DS5000FP will divide this common RAM into user programmable code and data segments. This Partition can be selected at program loading time, but can be modified anytime later. It will decode memory access to the SRAM, communicate via its Byte-wide bus and write-protect the memory portion designated as ROM.
Combining program and data storage in one device saves board space and cost. The DS5000FP can also access a second 32 kbytes of NV RAM but this area is restricted to data memory. For a user that wants a pre-constructed module using the DS5000FP, RAM, lithium cell, and optional real time clock; the DS2250(T) and DS5000(T) are available and described in separate data sheets. More details are also contained in the User’s Guide section of the Secure Microcontroller Data Book.

FEATURES
*8051-compatible microprocessor adapts to task
- Accesses between 8kB and 64kB of nonvolatile SRAM
- In-system programming via on-chip serial port
- Can modify its own program or data memory
- Accesses memory on a separate Bytewide bus
*Crashproof operation
- Maintains all nonvolatile resources for over 10 years
- Power-fail Reset
- Early Warning Power-fail Interrupt
- Watchdog Timer
- User-supplied lithium battery backs user SRAM for program/data storage
*Software security
- Executes encrypted programs to prevent observation
- Security lock prevents download
- Unlocking destroys contents
*Fully 8051-compatible
- 128 bytes scratchpad RAM
- Two timer/counters
- On-chip serial port
- 32 parallel I/O port pins

DS5000FP-16

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