Optional Command Support Segment

3140

If bit twelve is set in the XTID header then the following word is added to the XTID. Bit 3141

fields that are left as zero indicate that the tag does not support that feature. The 3142

description of the features is as follows. 3143

Bit Position in

Segment

Field Description

4 – 0 Max EPC Size This five bit field shall indicate the maximum size that can be programmed into the first five bits of the PC. 5 Recom Support If this bit is set the tag supports recommissioning as

specified in [UHFC1G2].

6 Access If this bit is set the it indicates that the tag supports the access command.

Bit Position in Segment Field Description 7 Separate Lockbits

If this bit is set it means that the tag supports lock bits for each memory bank rather than the simplest

implementation of a single lock bit for the entire tag.

8 Auto UMI

Support

If this bit is set it means that the tag automatically sets its user memory indicator bit in the PC word.

9 PJM Support If this bit is set it indicates that the tag supports phase jitter modulation. This is an optional modulation mode supported only in Gen 2 HF tags.

10 BlockErase

Supported

If set this indicates that the tag supports the BlockErase command. How the tag supports the BlockErase

command is described in Section 16.2.4. A manufacture may choose to set this bit, but not include the BlockWrite and BlockErase field if how to use the command needs further explanation through a database lookup.

11 BlockWrite

Supported

If set this indicates that the tag supports the BlockWrite command. How the tag supports the BlockErase

command is described in Section 16.2.4. A manufacture may choose to set this bit, but not include the BlockWrite and BlockErase field if how to use the command needs further explanation through a database lookup.

12 BlockPermaLo

ck Supported

If set this indicates that the tag supports the

BlockPermaLock command. How the tag supports the BlockPermaLock command is described in

Section 16.2.5. A manufacture may choose to set this bit, but not include the BlockPermaLock and User Memory field if how to use the command needs further

explanation through a database lookup. 15 – 13 [RFU] These bits are RFU and should be set to zero.

Table 44. Optional Command Support XTID Word 3144

16.2.4 BlockWrite and BlockErase Segment

3145

If bit eleven of the XTID header is set then the XTID shall include the four-word 3146

BlockWrite and BlockErase segment. To indicate that a command is not supported, the 3147

tag shall have all fields related to that command set to zero. This SHALL always be the 3148

case when the Optional Command Support Segment (Section 16.2.3) is present and it 3149

indicates that BlockWrite or BlockErase is not supported. The descriptions of the fields 3150

are as follows. 3151

Bit Position in Segment Field Description 7 – 0 Block Write Size

Max block size that the tag supports for the BlockWrite command. This value should be between 1-255 if the BlockWrite command is described in this field.

8 Variable Size

Block Write

This bit is used to indicate if the tag supports BlockWrite commands with variable sized blocks.

• If the value is zero the tag only supports writing blocks exactly the maximum block size indicated in bits [7-0].

• If the value is one the tag supports writing blocks less than the maximum block size indicated in bits [7-0]. 16 – 9 Block Write

EPC Address Offset

This indicates the starting word address of the first full block that may be written to using BlockWrite in the EPC memory bank.

17 No Block

Write EPC address alignment

This bit is used to indicate if the tag memory architecture has hard block boundaries in the EPC memory bank. • If the value is zero the tag has hard block boundaries

in the EPC memory bank. The tag will not accept BlockWrite commands that start in one block and end in another block. These block boundaries are

determined by the max block size and the starting address of the first full block. All blocks have the same maximum size.

• If the value is one the tag has no block boundaries in the EPC memory bank. It will accept all BlockWrite commands that are within the memory bank.

25 – 18 Block Write User Address Offset

This indicates the starting word address of the first full block that may be written to using BlockWrite in the User memory.

Bit Position in Segment Field Description 26 No Block Write User Address Alignment

This bit is used to indicate if the tag memory architecture has hard block boundaries in the USER memory bank. • If the value is zero the tag has hard block boundaries

in the USER memory bank. The tag will not accept BlockWrite commands that start in one block and end in another block. These block boundaries are

determined by the max block size and the starting address of the first full block. All blocks have the same maximum size.

• If the value is one the tag has no block boundaries in the USER memory bank. It will accept all

BlockWrite commands that are within the memory bank.

31 – 27 [RFU] These bits are RFU and should be set to zero. 39 –32 Size of Block

Erase

Max block size that the tag supports for the BlockErase command. This value should be between 1-255 if the BlockErase command is described in this field. 40 Variable Size

Block Erase

This bit is used to indicate if the tag supports BlockErase commands with variable sized blocks.

• If the value is zero the tag only supports erasing blocks exactly the maximum block size indicated in bits [39-32].

• If the value is one the tag supports erasing blocks less than the maximum block size indicated in bits [39- 32].

48 – 41 Block Erase EPC Address Offset

This indicates the starting address of the first full block that may be erased in EPC memory bank.

Bit Position in Segment Field Description 49 No Block Erase EPC Address Alignment

This bit is used to indicate if the tag memory architecture has hard block boundaries in the EPC memory bank. • If the value is zero the tag has hard block boundaries

in the EPC memory bank. The tag will not accept BlockErase commands that start in one block and end in another block. These block boundaries are

determined by the max block size and the starting address of the first full block. All blocks have the same maximum size.

• If the value is one the tag has no block boundaries in the EPC memory bank. It will accept all BlockErase commands that are within the memory bank.

57 – 50 Block Erase User Address Offset

This indicates the starting address of the first full block that may be erased in User memory bank.

58 No Block

Erase User Address Alignment

Bit 58: This bit is used to indicate if the tag memory architecture has hard block boundaries in the USER memory bank.

• If the value is zero the tag has hard block boundaries in the USER memory bank. The tag will not accept BlockErase commands that start in one block and end in another block. These block boundaries are

determined by the max block size and the starting address of the first full block. All blocks have the same maximum size.

• If the value is one the tag has no block boundaries in the USER memory bank. It will accept all

BlockErase commands that are within the memory bank.

63 – 59 [RFU] These bits are reserved for future use and should be set to zero.

Table 45. XTID Block Write and Block Erase Information 3152