DS2250(T)
DS2250(T)
Soft Microcontroller Module
FEATURES
PIN ASSIGNMENT
• 8–bit8051compatiblemicrocontrolleradaptstotask–
at–hand:
–
–
–
8K, 32K, or 64K bytes of nonvolatile RAM for
program and/or data memory storage
1
20
21
40
Initial downloading of software in end system
via on–chip serial port
Capable of modifying its own program and/or
data memory in end use
40-PIN SIMM
• High–reliability operation:
–
Maintains all nonvolatile resources for 10 years
in the absence of V
CC
–
–
–
Power–fail reset
Early warning power–fail interrupt
Watchdog timer
• Software Security Feature:
–
Executes encrypted software to prevent unau-
thorized disclosure
• On–chip, full–duplex serial I/O ports
• Two on–chip timer/event counters
• 32 parallel I/O lines
• Compatible with industry standard 8051 instruction
set
• Permanently Powered real time clock
DESCRIPTION
The DS2250(T) Soft Microcontroller Module is a fully
8051compatible8–bitCMOSmicrocontrollerthatoffers
“softness” in all aspects of its application. This is ac-
complishedthroughthecomprehensiveuseofnonvola-
tile technology to preserve all information in the ab-
sence of system V
memory space is implemented using 8K, 32K, or 64K
bytes of nonvolatile CMOS SRAM. Furthermore, inter-
nal data registers and key configuration registers are
also nonvolatile. An optional real time clock gives per-
manently powered timekeeping. The clock keeps time
to a hundredth of a second using an on–board crystal.
All nonvolatile memory and resources are maintained
for over 10 years at room temperature in the absence of
power.
.
The internal program/data
CC
ECopyright 1995 by Dallas Semiconductor Corporation.
All Rights Reserved. For important information regarding
patents and other intellectual property rights, please refer to
Dallas Semiconductor data books.
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