Intermec IF2 Basic Reader Interface Programmer's Reference Manual (BRI version - Page 39

PC, RSSI, STRING(memory_bank:address, length

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Chapter 3 - Understanding BRI Programming Elements The ISO 18000-6C standard permits up to 66 bytes (CRC-16, PC-16, 31-UII data words) in this bank but the tag manufacturer may supply less than 31 UII data words. An attempt to write data beyond what exists in the tag will result in a write error. You should be careful writing bytes 0 to 3 on a tag. Bytes 0 and 1 correspond to the CRC-16. The tag recalculates the CRC-16 value each time the tag is powered on. Bytes 2 and 3 correspond to the protocol (PC) control word which includes the data length field, the EPC/ISO bit, and the header bits. You must be careful to encode the PC correctly. The data length field is the word count of the PC plus the UII data words. Note: Locations 0 through 3 should not be written and the starting address for the command should be 4 or greater. PC The PC keyword is used to display the protocol control bits of an EPCglobal Class 1 Gen 2 tag. This is a read-only field. The displayed value is a hexadecimal value of 4, 8, or 12 digits. The first set of four digits represents the tag protocol control (PC) word. The second set of four digits represents the first extended protocol control word (XPC_1) for the tag. The third set of four digits represents the second extended protocol control word (XPC_2) for the tag. RSSI The RSSI keyword is a negative integer data field associated with the received signal strength of the tag being returned for the current tag operation. The minimum value for RSSI is -128 dBm, and the maximum value is 0 dBm. STRING(memory_bank:address, length) You can also use the shortcut name STR. Data types declared as STRING can range in length from zero to the length of the data space as specified by the length parameter. All STRING data types are represented as the printable ASCII character set. If a value is not in the ASCII printable range (32 to 127), the data is displayed in a format that is dependent on the host device. If a string data type is defined, it should contain only printable ASCII characters. The memory_bank parameter is optional and only applies to EPCglobal Class 1 Gen 2 tags. For a list of valid values for memory_bank, see the Valid Memory Bank Values table in the data field definition: "HEX(memory_bank:address, length)" on page 24. The address parameter can range from 0 to the length of the data space. If an address is larger than the space available on the tag, the response depends on the tag type: • For ISO 18000-6B tags, the address wraps to the beginning of the tag memory. • For EPCglobal Class 1 Gen 2 tags and other tag types, an error is returned for out-of-range addresses. Basic Reader Interface Programmer Reference Manual 27

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Chapter 3 — Understanding BRI Programming Elements
Basic Reader Interface Programmer Reference Manual
27
The ISO 18000-6C standard permits up to 66 bytes (CRC-16, PC-16, 31-UII data
words) in this bank but the tag manufacturer may supply less than 31 UII data
words. An attempt to write data beyond what exists in the tag will result in a write
error.
You should be careful writing bytes 0 to 3 on a tag. Bytes 0 and 1 correspond to the
CRC-16. The tag recalculates the CRC-16 value each time the tag is powered on.
Bytes 2 and 3 correspond to the protocol (PC) control word which includes the data
length field, the EPC/ISO bit, and the header bits. You must be careful to encode the
PC correctly. The data length field is the word count of the PC plus the UII data
words.
PC
The PC keyword is used to display the protocol control bits of an EPCglobal Class 1
Gen 2 tag. This is a read-only field. The displayed value is a hexadecimal value of 4, 8,
or 12 digits. The first set of four digits represents the tag protocol control (PC)
word. The second set of four digits represents the first extended protocol control
word (XPC_1) for the tag. The third set of four digits represents the second extended
protocol control word (XPC_2) for the tag.
RSSI
The RSSI keyword is a negative integer data field associated with the received signal
strength of the tag being returned for the current tag operation. The minimum
value for RSSI is -128 dBm, and the maximum value is 0 dBm.
STRING(memory_bank:address, length)
You can also use the shortcut name STR.
Data types declared as STRING can range in length from zero to the length of the
data space as specified by the
length
parameter.
All STRING data types are represented as the printable ASCII character set. If a value
is not in the ASCII printable range (32 to 127), the data is displayed in a format that
is dependent on the host device. If a string data type is defined, it should contain
only printable ASCII characters.
The
memory_bank
parameter is optional and only applies to EPCglobal Class 1 Gen
2 tags. For a list of valid values for
memory_bank
, see the Valid Memory Bank Values
table in the data field definition:
“HEX(memory_bank:address, length)” on
page 24
.
The
address
parameter can range from 0 to the length of the data space. If an address
is larger than the space available on the tag, the response depends on the tag type:
•
For ISO 18000-6B tags, the address wraps to the beginning of the tag memory.
•
For EPCglobal Class 1 Gen 2 tags and other tag types, an error is returned for
out-of-range addresses.
Note:
Locations 0 through 3 should not be written and the starting address for the
command should be 4 or greater.