User's Manual

3-3 Memory Check Function I.CODE1 Mode Only

3-3

3-6

By adding a check code to the data in the Tag, you can detect data errors

due to the Tag memory (EEPROM) being overwritten, service life, and

unforeseen factors.

The check code uses the CRC code of the generating polynomial X

+ X

+ 1.

A memory check is performed using the Memory Check Command (MC),

which writes the check code, and the Memory Calculation Command

(MK), which verifies the check code. In the check block defined using the

header page and the number of pages, the target calculation area is the

area except for the last page of the block, and the last page is the check

code area. The check code uses two bytes in the check code area.

When a check code write command is sent, the CRC code for the data in

the target calculation area is calculated, and written to the check code

area. When the data verification command is sent, the CRC code for the

data in the target calculation area is calculated, and compared with the

data in the check code area. If these match, the number 75 is returned in

the response code to show that the data is normal. If they do not match,

the number 76 is returned to show that there is a data error.

Example: Memory check is performed when check block header page is 00

and the number of check blocks is 0B.

・

3-3-1 Usage

After writing the data, calculate and write the check code using the

Memory Check Command (MC), and before reading the data, verify the

check code using the Memory Calculation Command (MK). You can detect

data corruption in advance within the Tags that are not being accessed.

Write data

Write stage

Calculate check code

Verify check code

Read stage

Read data

： This Command is for I.CODE1 Mode Only. The command is not available in ISO mode:

Check code area

Check code

Calculation area