User's Manual

HF Mifare Easy Module V1.0
ACG Identification Technologies GmbH 54
7.4.3.18 Write value block
This command formats a block as a value block containing a 32-bit value. A read
after write is performed automatically. Value blocks need a complete 16-byte block
due to redundant storage. A successful login is required to run the command.
Command
Command Data
'wv' Value block (1 byte)
Value (4 bytes)
Answer
Answer Description
Data Written value (4 bytes)
'I' Error: value block failure
'F' Error: increment failure
'N' Error: No tag in field
'U' Error: Read after write failure
Example
Command Description
wv05010055EF Writes value 010055EFh to block 5.
7.4.3.18.1 Invalid value 'I'
The value read back after the write value instruction is a not a value block. Data was
written corruptly.
7.4.3.18.2 Write failure 'F'
Additional to a data read error caused by bad transmission conditions, this error
appears if a sector is addressed which is not located in the authenticated sector.
7.4.3.18.3 No tag error 'N'
This error is returned if no tag is present or the card does not respond.