Memory mapping

SR176

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4

Memory mapping

The SR176 is organized as 16 blocks of 16 bits, as shown in Figure 12.

The first four blocks, from location 0 to 3, are used to store read-only data. They store the

64-bit UID. This value cannot be modified.

Blocks from locations 4 to 14 offer a 176-bit EEPROM user area in which the application can

store its data values. Block 15 contains the OTP LOCK_REG and the programmed Chip_ID.

The PROTECT_BLOCK command is used to lock write access to blocks 4 to 15 in groups of

two blocks.

The GET_PROTECTION command gives the status of the protection of blocks 4 to 15.

Figure 12.

SR176 memory mapping

4.1

Device identification

The SR176 has a 64-bit Unique Identifier (UID) which is written by STMicroelectronics

during the manufacturing process. The UID is unique for each tag and cannot be altered. It

is stored in a Read Only Memory area (ROM). In the SR176, the UID is stored in the first

four blocks of the memory in blocks 0 to 3.

Block

Address

MSb

LSb

b15

16-bit block

b7

b0

b8

Description

0

1

2

3

UID0

UID1

UID2

UID3

64-bit UID

ROM

4

5

6

7

8

9

10

11

12

13

14

15

User Area

User Area

User Area

User Area

User Area

User Area

User Area

User Area

User Area

User Area

User Area

Lockable EEPROM

Lockable EEPROM

Lockable EEPROM

Lockable EEPROM

Lockable EEPROM

Lockable EEPROM

Chip_ID

Reserved

OTP LOCK_REG

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