User's Manual

ACR1281U
 Advanced Card Systems Ltd. Page 37 of 81
2.5.2 Read Value Block
The “Read Value Block command” is used for retrieving the value from the value block. This
command is only valid for value block.
Table 2.5.2-1a: Read Value Block APDU Format (5 Bytes)
Command Class INS P1 P2 Le
Read Value
Block
FF B1 00 Block
Number
00
Block Number (1 Byte):
The value block to be accessed.
Table 2.5.2-1b: Read Value Block Response Format (4 + 2 Bytes)
Response Data Out
Result Value
{MSB .. LSB}
SW1 SW2
Value (4 Bytes):
The value returned from the card. The value is a signed long integer (4 bytes).
E.g. 1: Decimal –4 = {0xFF, 0xFF, 0xFF, 0xFC}
Value
MSB LSB
FF FF FF FC
E.g. 2: Decimal 1 = {0x00, 0x00, 0x00, 0x01}
Value
MSB LSB
00 00 00 01
Table 2.5.3-1c: Read Value Block Response Codes
Results SW1 SW2 Meaning
Success 90 00 The operation is completed
successfully.
Error 63 00 The operation is failed.