DS2252T Просмотр технического описания (PDF) - Dallas Semiconductor -> Maxim Integrated

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DS2252T

Secure Microcontroller Module

Dallas Semiconductor -> Maxim Integrated 

DS2252T

Using a security system based on the DS5002FP, the

DS2252T protects the memory contents from disclo-

sure. It loads program memory via its serial port and

encrypts it in real–time prior to storing it in SRAM. Once

encrypted, the RAM contents and the program flow are

unintelligible. The real data exists only inside the pro-

cessor chip after being decrypted. Any attempt to dis-

cover the on–chip data, encryption keys, etc., results in

its destruction. Extensive use of nonvolatile lithium

backed technology create a microcontroller that retains

data for over 10 years at room temperature, but which

can be erased instantly if tampered with. The DS2252T

even interfaces directly to external tamper protection

hardware.

The DS2252T provides a permanently powered real

time lock with interrupts for time stamp and date. It

keeps time to one hundredth of a second using its on–

board 32 KHz crystal.

Like other Secure Microcontrollers in the family, the

DS2252T provides crashproof operation in portable

systems or systems with unreliable power. These fea-

tures include the ability to save the operating state,

Power–fail Reset, Power–fail Interrupt, and Watchdog

Timer. All nonvolatile memory and resources are main-

tained for over 10 years at room temperature in the

absence of power.

A user loads programs into the DS2252T via its on–chip

Serial Bootstrap Loader. This function supervises the

loading of software into NVRAM, validates it, then

becomes transparent to the user. It also manages the

loading of new encryption keys automatically. Software

is stored in on–board CMOS SRAM. Using its internal

Partitioning, the DS2252T can divide a common RAM

into user selectable program and data segments. This

Partition can be selected at program loading time, but

can be modified anytime later. The microcontroller will

decode memory access to the SRAM, access memory

via its Byte–wide bus and write–protect the memory por-

tion designated as program (ROM).

A detailed summary of the security features is provided

in the User’s Guide section of the Secure Microcontrol-

ler data book. An overview is also available in the

DS5002FP data sheet.

ORDERING INFORMATION

PART NUMBER

DS2252T–32–16

DS2252T–64–16

DS2252T–128–16

RAM SIZE

32K bytes

64K bytes

128K bytes

MAX CRYSTAL SPEED

16 MHz

16 MHz

16 MHz

TIMEKEEPING?

Yes

Yes

Yes

Operating information is contained in the User’s Guide section of the Secure Microcontroller Data Book. This data

sheet provides ordering information, pinout, and electrical specifications.

121395 2/14

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