DS2432 Datasheet, PDF (1/30 Pages) Dallas Semiconductor – 1k-Bit Protected 1-Wire EEPROM with SHA-1 Engine

www.dalsemi.com
Preliminary
DS2432
1k-Bit Protected 1-Wire^™
EEPROM with SHA-1 Engine
FEATURES
1128 bits of 5V EEPROM memory parti-
tioned into four pages of 256 bits, a 64-bit
write-only secret and up to 5 general purpose
read/write registers
On-chip 512-bit SHA-1 engine to compute
160-bit Message Authentication Codes
(MAC) and to generate secrets
Write access requires knowledge of the secret
and the capability of computing and transmit-
ting a 160-bit MAC as authorization
Secret and data memory can be write-pro-
tected (all or page 0 only) or put in EPROM-
emulation mode (“write to 0”, page 1)
Unique, factory-lasered and tested 64-bit reg-
istration number assures absolute traceability
because no two parts are alike
Built-in multidrop controller ensures compati-
bility with other 1-Wire net products
Reduces control, address, data and power to a
single data pin
Directly connects to a single port pin of a mi-
croprocessor and communicates at up to 16.3k
bits per second
Overdrive mode boosts communication speed
to 142k bits per second
Low cost 6-lead TSOC surface mount pack-
age, or solder-bumped Flipchip package
Reads and writes over a wide voltage range of
2.8V to 5.25V from -40°C to +85°C
PIN ASSIGNMENT
TSOC (150mil)
GND ¹
1-WIRE 2
NC 3
6 NC
5 NC
4 NC
top view
side view
top view
See www.dalsemi.com for mechanical
specifications of packages.
ORDERING INFORMATION
DS2432P
6-lead TSOC package
DS2432P/T&R Tape & Reel DS2432P
DS2432X
Flipchip package, tape & reel
DESCRIPTION
The DS2432 combines 1024 bits of EEPROM, a 64-bit secret, an 8-byte register/control page with up to 5
user read/write bytes, a 512-bit SHA-1 engine and a fully-featured 1-Wire interface in a single chip. Each
DS2432 has its own 64-bit ROM registration number that is factory lasered into the chip to provide a
guaranteed unique identity for absolute traceability. Data is transferred serially via the 1-Wire protocol,
which requires only a single data lead and a ground return. The DS2432 has an additional memory area
called the scratchpad that acts as a buffer when writing to the main memory, the register page or when
installing a new secret. Data is first written to the scratchpad from where it can be read back. After the
data has been verified, a copy scratchpad command will transfer the data to its final memory location,
provided that the DS2432 receives a matching 160-Bit MAC. The computation of the MAC involves the
secret and additional data stored in the DS2432 including the device’s registration number. Only a new
secret can be loaded without providing a MAC. The SHA-1 engine can also be activated to compute
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