The ISO18000-6C electronic tag is an electronic tag that complies with the ISO 18000-6C air interface protocol. Similarly, electronic tags conforming to the ISO18000-6D protocol become ISO18000-6D electronic tags.
In order to enable customers to use the RMU900+ reader module more flexibly and apply the RMU900+ reader/writer module to the actual engineering environment, the ISO18000-6C data storage space and the data encryption process of the reader and the electronic tag communication are briefly described. To facilitate customers to familiarize themselves with relevant knowledge as soon as possible. This article describes the simple, detailed content, please refer to the ISO18000-6C protocol standard.
According to the protocol, the tag memory is logically divided into four banks, and each bank may consist of one or more memories. As shown in Figure 2.1. The four banks are:
a) Reserve memory
Reserved memory should contain kill passwords and access passwords. The kill password should be stored in the memory address 00h to 1Fn. The access password should be stored in the memory address from 20h to 3Fn.
b) EPC memory
The EPC memory should contain the CRC-16 in the 00h to 0Fh memory locations, the Protocol-Control (PC) bits in the 10h to 1Fh memory address, and the EPC in 20h. The PC is divided into EPC lengths of 10h to 14Fh memory locations, RFU bits of 15h to 17Fh memory locations, and Number System Identifiers (NSI) in 18h to 1Fh memory locations. CRC-16, PC, and EPC should preferentially store MSBs (EPC's The MSB should be stored in the 20h storage location). Note:
c) TID memory
The TID memory shall contain 8-bit ISO15963 distribution class identification (111000102 for EPCglobal) for 00h to 07n memory locations, 12-bit task mask design identification (EPCglobal member free) for storage locations 08h to 13n, and 12 bits for 14h to 1Fn storage locations Label model number. The tag may contain tag specifying data and provider specifying data (for example, tag number) in a TID memory of 1Fn or more.
d) User memory
User memory allows user-specified data to be stored. This memory organization is user defined.
2.1 Reserved memory
◆ Kill password
Keep the memory 00h to 1Fh storage electronic tag kill password, kill the password is 1 word, ie 2 bytes. The default kill command for electronic tags is 0000h. The user can modify the kill instruction. The user can latch the kill password. Once latched, the user must provide the correct access password to read and write the kill password.
◆ Access password
The memory access password for the 20h to 3Fh storage electronic tag is reserved. The access password is 1 word, ie 2 bytes. The default access command for electronic tags is 0000h. The user can modify the access instruction. The user can latch the access password. Once latched, the user must provide the correct access password to read and write the access password.
2.2 EPC memory
◆ CRC-16 (Cyclic Redundancy Check)
Cyclic redundancy check bits, 16 bits. When powering up, the tag should calculate CRC-16 by the number of PC (PC+EPC) words specified by the first five bits of the PC instead of the entire EPC memory length.
◆ PC (Protocol Control, Protocol Control)
The PC bit contains physical layer information backscattered with its EPC during the inventory operation. The EPC memories 10h to 1Fn store addresses with 16 PC bits. The PC bit values are defined as follows:
◆ 10h-14n bits: The length of the label backscattered (PC + EPC), all words are:
000002: One word (EPC memory 10h-1Fn memory address)
000012: Two words (EPC memory 10h-2Fn memory address)
000102: Two words (EPC memory 10h-3Fn memory address)
111112: 32 words (EPC memory 10h-1FFn memory address)
◆ 15h-17h: RFU (Type 1 label is 0002)
◆ 18h—1F h-bit: The default value is 000000002 and can include Counting System Identification (NSI) as defined by ISO/IEC 15961. NSI's MSB is stored in the 18h storage location.
The default (unprogrammed) PC value should be 0000h.
During the truncation response, the tag replaces 00002 with the PC bit.
◆ EPC (Electronic Product Code, product electronic code)
The EPC is stored in the EPC memory starting with the 20h memory address, MSB first. The interrogator may issue a select command, including all or part of the regulated EPC. The interrogator can issue an ACK command to backscatter the tag with its PC, EPC, and CRC-16 (this tag can truncate the answer in certain circumstances - see 18.104.22.168.1.1). Finally, the interrogator can issue a Read command to read the entire or partial EPC.
[Note] PC+EPC is also called UII
2.3 TID memory
The TID memory shall contain 8-bit ISO15963 distribution class identification (111000102 for EPCglobal) for 00h to 07n memory locations, 12-bit task mask design identification (EPCglobal member free) for storage locations 08h to 13n, and 12 bits for 14h to 1Fh storage locations Label model number. The tag can contain tag designation data and provider designation data (for example, tag number) in a TID memory above 1Fh.
2.4 user memory
User memory allows user-specified data to be stored.
To prevent unauthorized writes and kills, the ISO18000-6C tag provides latch/unlock operations. The 32-bit access password protects the latch/unlock operation of the tag, while the 32-bit kills the kill operation of the password protection tag. The user can set the kill password and the access password in the reserved memory of the electronic tag.
3.2 Two states of data manipulation
When the tag is in the OPEN or SECURED state, it can perform data operations (read, write, erase, latch/unlock, kill). When the tag's access password is all zero, or the user enters the access code correctly, the tag is in the SECURED state. When the tag's access password is not zero, and the user does not enter the access password or the entered access password is incorrect, the tag is in the OPEN state. The latch/unlock operation of the tag can only be performed in the SECURED state.
*Note: When the user performs a latch/unlock operation, one of the following two conditions must be satisfied:
a. The tag's access password is all zero.
b. Provide the correct access password.
3.3 Latch/unlock operation of each memory area
After latching the reserved area, the user cannot read or write the reserved area. This is to prevent unauthorized users from reading the kill password and access password of the label. After latching the other three memory areas (EPC memory area, TID memory area, and user memory area), the user cannot write to the corresponding memory area but can perform a read operation.
3.4 Lock Type
The tag supports three lock types:
a. After the tag is locked, it can only be written in the SECURED state (read-write for reserved memory), and cannot be written in the OPEN state (read-write for reserved memory).
b. Tags can be written in both the OPEN and SECURED states (read-write for reserved memory), and the locked state can never be overwritten.
c. The tag cannot be written in any state (read-write for reserved memory), and it cannot be unlocked permanently. [Note] This operation is used with caution. Once a memory area is permanently latched, the memory area data cannot be read or written again! ! !
This section briefly describes the LOCK instruction
The Lock command contains the 20-bit payload defined as follows:
The first 10 payload bits are mask bits. The tag should explain these bit values as follows:
Mask=0: Ignore related action fields and keep the current lock settings.
Mask=1: Execute the relevant action field and override the current lock setting.
The last 10 payload bits are action bits. The tag should explain these bit values as follows:
Action=0: Cancel the lock of the relevant storage location.
ISO18000-6C electronic tag data storage space and data encryption instructions
Action=1: Confirm that the relevant storage location is locked or permanently locked.