MAXIM DS2502P-E64+

The DS2502-E64 is a variant of the DS2502 1024-bit Add-Only Memory. It differs from the standard DS2502 in its custom ROM family code 89h, and the UniqueWare Identifier 5E7h in place of the upper 12 bits of the standard ROM serialization field. Otherwise, the electrical and logical behavior is identical to that of the DS2502. The first 32 bytes of the DS2502-E64’s EPROM memory contain a globally unique 64-bit node address (EUI-64) and are write-protected. The data structure follows the conventions of UniqueWare devices using Default Data Structure. This format is also known as UDP (universal data packet) and is commonly used in 1-Wire APIs. The data record starts with a length byte (0Ch) and the 4-byte UniqueWare Project ID 00001128h. The next eight bytes contain the EUI-64 global identifier (node address) which consists of an incrementing 40-bit extension identifier and the IEEE-assigned 24-bit company ID value 006035h. An inverted 16-bit CRC ends the data record. The remaining bytes of the 32-byte memory page remain unprogrammed. The four bytes at memory addresses 01h to 04h contain the UniqueWare Project ID 00001128h. The two bytes at addresses 0Dh and 0Eh are the inverted 16-bit CRC over the length byte, Project ID and EUI-64 value. The least significant byte of the CRC is stored at address 0Dh. This CRC is generated according to the standardized CRC16 polynomial function X^16 + X^15 + X^2 + 1. The contents of the memory address range 0Fh to 1Fh is FFh. These cells cannot be altered since the whole memory page is write-protected. The memory range from 20h to 7Fh, however, is user - programmable. It can be write-protected by programming the corresponding write-protect bit in the status memory of the DS2502-E64.

• IEEE-approved factory programmed 64-bit node address chip (EUI-64) with 768 bits user-programmable OTP-EPROM communicates with the economy of one signal plus ground
• Meets the node identification requirements of IEEE Standard 1394-1995 (FireWire)
• 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 products
• Device is an “add only” memory where additional data can be programmed into EPROM without disturbing existing data
• Reduces control, address, data, power and programming signals to a single pin
• Directly connects to a single port pin of a microprocessor and communicates at up to 16.3k bits per second
• Presence detector acknowledges when reader first applies voltage
• Low cost TO-92 or TSOC surface mount packages
• Reads over a wide voltage range of 2.8V to 6.0V from -40℃ to +85℃; programs at 11.5V to 12.0V from -40℃ to +50℃