ACR122T – Application Programming Interface
Version 2.02
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5.5. Value Block Related Commands
The data block can be used as value block for implementing value-based applications.
5.5.1.
Value Block Operation
The “Value Block Operation command” is used for manipulating value-based transactions. E.g.
Increment a value of the value block etc.
Value Block Operation APDU Format (10 Bytes)
Command
Class INS
P1
P2
Lc
Data In
Value Block
Operation
FFh
D7h 00h
Block
Number 05h VB_OP
VB_Value
(4 Bytes)
{MSB .. LSB}
Where:
Block Number:
1 Byte. The value block to be manipulated.
VB_OP:
1 Byte.
0x00h = Store the VB_Value into the block. The block will then be converted to a value block.
0x01h = Increment the value of the value block by the VB_Value. This command is only valid
for value block.
0x02h = Decrement the value of the value block by the VB_Value. This command is only valid
for value block.
VB_Value:
4 Bytes. The value used for value manipulation. The value is a signed long
integer (4 bytes).
Example 1:
Decimal –4 = {0xFFh, 0xFFh, 0xFFh, 0xFCh}
VB_Value
MSB
LSB
FFh
FFh
FFh
FCh
Example 2:
Decimal 1 = {0x00h, 0x00h, 0x00h, 0x01h}
VB_Value
MSB
LSB
00h
00h
00h
01h
Value Block Operation Response Format (2 Bytes)
Response
Data Out
Result
SW1 SW2
Response Codes
Results SW1 SW2
Meaning
Success
90 00h
The operation completed successfully.
