MAX66120 MAXIM [Maxim Integrated Products], MAX66120 Datasheet - Page 4

• Manufacturer Part Number: MAX66120
• Description: ISO 15693-Compliant 1Kb Memory Fob Powered Entirely Through the RF Field
• Manufacturer: MAXIM [Maxim Integrated Products]

ISO 15693-Compliant 1Kb Memory Fob
Figure 4. Memory Map
bit locations 49 to 56 identifies the chip manufacturer,
according to ISO/IEC 7816-6/AM1. This code is 2Bh
for Maxim. The code in the upper 8 bits is E0h. The
UID is read accessible through the Inventory and Get
System Information commands.
The memory of the MAX66120 is organized as 18
blocks of 8 bytes each. Figure 4 shows the memory
map. The first 16 blocks (block numbers 00h to 0Fh in
hexadecimal counting) are the user EEPROM, the area
for application-specific data. Four adjacent blocks are
also referred to as a page. Blocks 00h to 03h are
page 0, blocks 04h to 07h are page 1, blocks 08h to
0Bh are page 2, and blocks 0Ch to 0Fh are page 3.
Block 10h provides storage for user-programmable
parameters that are defined by the ISO 15693 stan-
dard. These are AFI and DSFID. The remaining bytes
(U1 to U6) are not defined by the communication stan-
dard; the application software can use them, e.g., for
4
NUMBER
BLOCK
_______________________________________________________________________________________
0Ah
0Bh
0Ch
0Dh
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Eh
0Fh
10h
11h
Detailed Memory Description
BP1
U1
0
(SEQUENCE LEFT TO RIGHT AS WRITTEN TO OR READ FROM DEVICE)
BP2
U2
1
BP3
U3
2
Page 0 User EEPROM R/(W)
Page 0 User EEPROM R/(W)
Page 0 User EEPROM R/(W)
Page 0 User EEPROM R/(W)
Page 1 User EEPROM R/(W)
Page 1 User EEPROM R/(W)
Page 1 User EEPROM R/(W)
Page 1 User EEPROM R/(W)
Page 2 User EEPROM R/(W)
Page 2 User EEPROM R/(W)
Page 2 User EEPROM R/(W)
Page 2 User EEPROM R/(W)
Page 3 User EEPROM R/(W)
Page 3 User EEPROM R/(W)
Page 3 User EEPROM R/(W)
Page 3 User EEPROM R/(W)
DATA BYTE NUMBER
BP4
U4
3
U-Lock
AFI
4
proprietary markings. Block 11h contains control bytes
that determine the operation of the individual pages
(EPROM-emulation mode or write protection of individ-
ual blocks), or to write protect U1 to U4, the AFI, and
the DSFID byte. The S-Lock byte, if programmed to a
suitable code, only protects itself from future changes.
The self-protection feature can be used to permanently
mark the fob as being “special,” as defined by the
application. Table 1 illustrates the relationship between
the controlling register in block 11h and the memory
area affected. Tables 2 and 3 specify the code assign-
ments to achieve the protection.
Besides the storage for 8 data bytes, each memory
block has 2 integrity bytes, which are not memory
mapped. The integrity bytes function as a MAX66120-
maintained, 16-bit write-cycle counter. Having reached
its maximum value of 65,535, the write-cycle counter
stops incrementing, but does not prevent additional
write cycles to the memory block. The integrity bytes
can be read through the Custom Read Block command.
AFI-Lock
DSFID
5
DSFID-
Lock
U5
6
S-Lock
U6
7
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
Write-Cycle Counter
INTEGRITY BYTES
LSB
MSB