User's Manual

HF Mifare Easy Module V1.0
ACG Identification Technologies GmbH 48
7.4.3.12 Read value block
Reads a value block. The command checks if data is in value block format. The read
value block command needs a successful login.
Command
Command Data
'rv' Value block (1 byte)
Answer
Answer Description
Data Read value (4 bytes)
'F' Error: General failure
'I' Error: value block failure
'N' Error: No tag in field
Example
Command Description
rv04 Reads value of block 4.
7.4.3.12.1 No value block 'I'
The value read back after the write value instruction is a not a value block. Data was
written corruptly.
7.4.3.12.2 No tag error 'N'
This means that the tag does not respond, because there is either no tag present or
none of the tags in the field is authenticated ('l' instruction).
7.4.3.12.3 General 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.