Mitsubishi DS5000TK manual Large Nonvolatile Memory, IN±SYSTEM Loading, High Reliability Operation

USER'S GUIDE

LARGE NONVOLATILE MEMORY

Soft Microprocessor chips provide nonvolatile memory control for standard CMOS SRAM. Modules combine the microprocessor chip with memory and lithium back- up. This includes conditionally write protected chip en- ables and a power supply output that switches between +5V and battery backup. The chip enables are decoded automatically based on user selectable memory sizes and partitioning. Partitioning defines the portion of memory used for program and data segments. Areas that are designated program are always write protected and are treated as ROM. Data areas are write protected only when power is out of tolerance. A large nonvolatile memory is useful for data logging and as flexible pro- gram storage. Memory will be retained for over 10 years at room temperature in the absence of power by ultra low±leakage lithium backed circuits.

IN±SYSTEM LOADING

The in±system programming capability lets the user up- date program code at any time. This program loading is supervised by a built±in ROM±based bootstrap loader. The ROM loader becomes transparent once program loading is complete. All devices allow program loading via the serial port. Data memory can also be retrieved using this loader function. Selected versions provide

other parallel loading protocols as well. In±system load- ing allows a system to be configured during final system test. A user can load custom software, diagnostic rou- tines, or calibration constants. If something changes or new features arise, the system can then be repro- grammed while in the field.

HIGH RELIABILITY OPERATION

Secure Microcontroller devices are designed for unsu- pervised operation in remote locations. Special fea- tures prevent a system from running out of control dur- ing transient events. These include a reset when power is out of tolerance; an early warning power±fail interrupt that allows software to save critical data; and a watch- dog to reset the micro if it gets lost. Also, nonvolatile memory allows software to save the operating state so a task can be resumed when power returns to normal.

The Secure Microcontroller family consists of three chips and their associated modules. Differences stem from I/O, memory access, and security features. The DS5000FP is used in DS2250T and DS5000(T) mod- ules. The DS5001FP is used in the DS2251T, and the DS5002FP is used in the DS2252T. A full selector guide with all memory and speed permutations is provided in the next section.

CHIP	DESCRIPTION	BYTE±WIDE BUS	SECURITY	PACKAGE
		MEMORY ACCESS
DS5000FP	Soft Microprocessor Chip	8, 32, 64*K bytes	Optional	80±pin QFP
DS5001FP	128K Microprocessor Chip	32, 64, 128K bytes	None	80±pin QFP
DS5002FP	Secure Microprocessor Chip	32, 64, 128K bytes	Maximum	80±pin QFP

MODULE	DESCRIPTION	ON±BOARD MEMORY	PACKAGE
DS2250(T)	DS5000FP on SIMM	8, 32, 64*K bytes	40±pin SIMM
DS5000(T)	DS5000FP in DIP Module	8, 32K bytes	40±pin DIP
DS2251T	DS5001FP on SIMM	32, 64, 128K bytes	72±pin SIMM
DS2252T	DS5002FP on SIMM	32, 64, 128K bytes	40±pin SIMM

*32K partitionable, 32K restricted to data memory only.

NOTES:

ªTº specifies optional on±board real±time clock.

128K byte versions provide fixed 64K program, 64K data segments. Other versions are partitionable.

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