Product Description
The DS1992/DS1993 memory iButtons (hereafter referred to as DS199x) are rugged read/write data
carriers that act as a localized database, easily accessible with minimal hardware. The nonvolatile
memory and optional timekeeping capability offer a simple solution to storing and retrieving vital
information pertaining to the object to which the iButton is attached. Data is transferred serially through
the 1-Wire protocol that requires only a single data lead and a ground return.
The scratchpad is an additional page that acts as a buffer when writing to memory. Data is first written to
the scratchpad where it can be read back. After the data has been verified, a copy scratchpad command
transfers the data to memory. This process ensures data integrity when modifying the memory. A 48-bit
serial number is factory lasered into each DS199x to provide a guaranteed unique identity that allows for
absolute traceability. The durable MicroCan package is highly resistant to environmental hazards such as
dirt, moisture, and shock. Its compact coin-shaped profile is self-aligning with mating receptacles,
allowing the DS199x to be easily used by human operators. Accessories permit the DS199x to be
mounted on almost any surface including plastic key fobs, photo-ID badges, and PC boards.
Applications include access control, work-in-progress tracking, electronic travelers, storage of calibration
constants, and debit tokens.
Copy Scratchpad
This command is used to copy data from the scratchpad to memory. After issuing the copy scratchpad
command, the user must provide a 3-byte authorization pattern. This pattern must exactly match the data
contained in the three address registers (TA1, TA2, E/S, in that order). If the pattern matches, the AA
(Authorization Accepted) flag is set and the copy begins. A logic 0 is transmitted after the data has been
copied until the user issues a reset pulse. Any attempt to reset the part is ignored while the copy is in
progress. Copy typically takes 30µs.
The data to be copied is determined by the three address registers. The scratchpad data from the
beginning offset through the ending offset is copied to memory, starting at the target address. Anywhere
from 1 to 32 Bytes can be copied to memory with this command. Whole Bytes are copied even if only
partially written. The AA flag is cleared only by executing a write scratchpad command.
Read Memory
The read memory command can be used to read the entire memory. After issuing the command, the user
must provide the 2-Byte target address. After the two Bytes, the user reads data beginning from the target
address and may continue until the end of memory, at which point logic 1's are read. It is important to
realize that the target address registers contains the address provided. The ending offset/data status Byte
is unaffected.
The hardware of the DS199x provides a means to accomplish error-free writing to the memory section.
To safeguard reading data in the 1-Wire environment and to simultaneously speed up data transfers, it is
recommended to packetize data into data packets of the size of one memory page each. Such a packet
would typically store a 16-bit CRC with each page of data to ensure rapid, error-free data transfers that
eliminate having to read a page multiple times to determine if the received data is correct or not. (See
Application Note 114 for the recommended file structure to be used with the 1-Wire environment.)
Product Characters:
| Item |
TM Card,TM iButton |
| Materal |
ABS ,Stainless Steel |
| Size |
16.25*5.89mm |
| Chip |
Compatible Ds1992-F5 |
| Memry |
1024 bit |
| Read-Write Method |
Contact |
| Working Temperature |
-40 ~ +85 degree |
| Sort |
Common TM card,magnetic TM Card |
| Crafts |
Engraving |
| Colors |
Red, green, blue, yellow, black, etc |
| Application |
Intelligent Community, Postal Service, Railway St, etc. |
Detailed Photos
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