Table of Contents
Advertisement
T A G M E M O R Y M A P - E XA M P L E
In the example below, 90-bytes of a 112-byte tag have been allocated to areas of the
memory map (leaving roughly 20% free for future uses). Because a short paragraph
of alphanumeric characters could quickly use all 90 bytes, creating an efficient
mapping scheme, which utilizes all 720-bits out of the 90-bytes allocated, will provide
a better use of tag space.
TAG ADDRESS
00 - 15
16 - 47
48 - 63
64 - 71
72 - 89
90 - 111
5 . 4 . 3
O p t i m i z i n g T a g M e m o r y
It should first be understood that data is always stored in tag memory in a binary form
(1's and 0's). Binary numbers are notated using the hexadecimal numbering system
(otherwise it would be too confusing looking at a screen full of 1's and 0's).
Below is an example of how hexadecimal notation simplifies the expressing of byte
values for the decimal number 52,882.
DECIMAL
52,882
In the above example, instead of using 5-bytes of data to store the ASCII bytes
representing characters 5, 2, 8, 8, and 2 (ASCII bytes: 0x35, 0x32, 0x38, 0x38, 0x32)
by simply writing two Hex bytes (0xCE and 0x92), 60% less tag memory is used to
store the same information.
When an alphabetical character is to be written to a tag, the ASCII value of the given
character is written to the tag. For example, to write a capital "D" (ASCII value 0x44),
the binary equivalent of the ASCII character 0x44 is written to the tag.
Additionally, if a database with look up values is used in the RFID application, the
logic level of the individual bits in the tag can be used to maximize tag memory.
.
C 0 4 0 5 - X X X - 0 1 O P E R A T O R ' S M A N U A L – R E V . 0 3
DESCRIPTION OF USAGE
Serial Number
Model Number
Manufacturing Date
Lot Number
Factory ID
Reserved
Table 5-1: Tag Memory Map Example
BINARY
1100111010010010
C H A P T E R 5 : R F I D T A G S
HEXADECIMAL
CE92
P A G E 4 9 O F 7 5
Advertisement
Table of Contents
