Siemens SIMATIC RF300 System Manual page 299

The typical sizes are 112 bytes, 256 bytes, 992 bytes EEPROM or 2000 bytes FRAM. Each ISO
transponder chip has an 8-byte long unique serial number (UID, read only). This UID is
transferred as an 8 byte value through a read command to address FFF0 with a length of 8.
OTP area
For the OTP area, a 16-byte address space is always reserved at the end of the memory area. The
blocks are divided up depending on the chip (see technical specifications). Note that the
corresponding addresses for the user data are therefore not available to the application when
the OTP area is used.
A total of 4 block addresses ("mapped" addresses) are provided:
• FF80
• FF84
• FF88
• FF8C
A write command to this block address with a valid length (4, 8, 12, 16 bytes depending on the
block address) protects the written data from subsequent overwriting.
Note
Exception Fujitsu chip (MDS D4xx and MDS D5xx)
The Fujitsu chip MB89R118 (MDS D4xx) has 8-byte blocks, which means that only 2 block
addresses have to be addressed: FF80 and FF88 with the length 8 and 16 bytes).
The Fujitsu chip MB89R112 (MDS D5xx) has 32 byte blocks and can therefore not be addressed
in the OTP area.
Note
Restriction to the use of the OTP
Observe the following restrictions when using OTP:
• The OTP write/lock command can only be sent in static operation.
• The OTP write/lock command can not be sent as a chained command.
The Fujitsu chip MB89R112 (MDS D5xx) has 32 byte blocks and can therefore not be addressed
in the OTP area.
Note
Use of the OTP area is not reversible
If you use the OPT area, you cannot undo it, because the OPT area can only be written to once.
SIMATIC RF300
System Manual, 02/2021, C79000-G8976-C345-09
8.1 Memory configuration of ISO the transponders
ISO transponder
299