DESCRIPTION

The DS2423 1-Wire? RAM with Counters is a fully static, read/write memory for battery operation in a low-cost, six-lead TSOC, surface-mount package. The memory is organized as 16 pages of 256 bits each. In addition, the device has four counters, two of them with external trigger inputs called A and B. Each of the counters is associated with a memory page. A counter without external trigger input increments each time data is written to the page it is associated with (write cycle counter). The counters triggered by inputs A and B, respectively, increment with every low-going pulse on their input. All counters are read only. They are automatically cleared to 0 when the battery is connected.

FEATURES

4096 bits of SRAM

Four 32-bit, read-only counters

Active-low external trigger inputs for two of the counters with on-chip debouncing compatible with reed and Wiegand switches

Unique, factory-lasered and tested 64-bit

registration number (8-bit family code + 48- bit serial number + 8-bit CRC tester) assures

absolute traceability because no two parts are alike

Memory partitioned into 16 256-bit pages in for packetizing data

256-bit scratchpad withstrict read/write protocols ensures integrity of data transfer

On-chip 16-bit CRC generator for safeguarding data transfers

Built-in multidrop controller ensures compatibility with other MicroLAN products

Directly connects to a single port pin of a microprocessor and communicates at up to

16.3kbits per second

Overdrive mode boosts communication speed to 142kbits per second

8-bit family code specifies device

communication requirements to reader

Presence detector acknowledges when reader first applies voltage

Compact, low cost 6-pin TSOC surface mount package

Reads, writes and counts over a wide voltage range of 2.8V to 5.5V from -40°C to +85°C