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 160-bit message authentication codes (MAC) when reading a memory page or to compute a new secret, instead of loading it. Applications of the DS2432 include intellectual property security, after-market management of consumables, and taper proof data carriers.
Key Features
Applications/Uses
1128 bits of 5V EEPROM memory partitioned 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 transmitting a 160-bit MAC as authorization
Secret and data memory can be write-protected (all or page 0 only) or put in EPROM-emulation mode ("write to 0", page 1)
Unique, factory-lasered and tested 64-bit registration number assures absolute traceability because no two parts are alike
Built-in multidrop controller ensures compatibility 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 microprocessor 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 package, or solder-bumped µCSP package
Reads and writes over a wide voltage range of 2.8V to 5.25V from -40°C to +85°C
Device Authentication
IEEE 1451.4 Sensor TEDS
Ink/Toner Cartridges
Medical Sensors
PCB Identification
Self-Configuration of Central Office Switches, Wireless Base Stations, PBXs, or other Modular-Based Rack Systems
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