srt512 STMicroelectronics, srt512 Datasheet - Page 18

• Manufacturer Part Number: srt512
• Description: 13.56 Mhz Short-range Contactless Memory Chip With 512-bit Eeprom And Anticollision Functions
• Manufacturer: STMicroelectronics

Memory mapping
4.4
4.4.1
18/49
System area
This area is used to modify the settings of the SRT512. It contains 3 registers:
OTP_Lock_Reg, Fixed Chip_ID and ST Reserved. See
A WRITE_BLOCK command in this area will not erase the previous contents. Selected bits
can thus be set from 1 to 0. All bits previously at 0 remain unchanged. Once all the 32 bits of
a block are at 0, the block is empty and cannot be updated any more.
Figure 16. System area
OTP_Lock_Reg
The 16 bits, b31 to b16, of the System Area (block address 255) are used as
OTP_Lock_Reg bits in the SRT512. They control the Write access to the 16 blocks 0 to 15
as follows:
The OTP_Lock_Reg bits cannot be erased. Once Write-protected, the blocks behave like
ROM blocks and cannot be unprotected. After any modification of the OTP_Lock_Reg bits, it
is necessary to send a SELECT command with a valid Chip_ID to the SRT512 in order to
load the block write protection into the logic.
This bit is set by ST during production tests on customer request. It cannot be modified by
the user.
Block
Address
When b16 is at 0, block 0 is Write-protected
When b17 is at 0, block 1 is Write-protected
When b18 is at 0, block 2 is Write-protected
When b19 is at 0, block 3 is Write-protected
When b20 is at 0, block 4 is Write-protected
When b21 is at 0, block 5 is Write-protected
When b22 is at 0, block 6 is Write-protected
When b23 is at 0, block 7 is Write-protected
When b24 is at 0, block 8 is Write-protected
When b25 is at 0, block 9 is Write-protected
When b26 is at 0, block 10 is Write-protected
When b27 is at 0, block 11 is Write-protected
When b28 is at 0, block 12 is Write-protected
When b29 is at 0, block 13 is Write-protected
When b30 is at 0, block 14 is Write-protected
When b31 is at 0, block 15 is Write-protected.
255
b31
MSB
OTP_Lock_Reg
b16 b15 b14
32-bit Block
1
ST Reserved
b8 b7
Figure 16
Fixed Chip_ID
(Option)
for a map of this area.
LSB
b0
Description
OTP
SRT512
ai13505