ACS ACK30 Smart Keyboard - Manual (Page 34)

ACR30 Reference Manual
Version 3.3 January 2009 Page 34 of 44
ACR30
Command format
Instruction
Code
Data length
81
H
00
H
Response data format
No response data
9.2.4.3. READ_DATA (*)
To read the specified number of bytes from the specified address of the card inserted.
Command format
Instruc
tion
Code
Data
length
Data
ADDR LEN
90
H
03
H
ADDR Byte address of first byte to be read from the card. The high byte of the address is
specified as the first byte of ADDR.
LEN Number N of data bytes to be read from the card (Len < 224 bytes)
Response data format
BYTE
1
BYTE
2
BYTE
3
... BYTE
N
PROT
1
... PROT
L
BYTE x Data bytes read from the card memory
PROT y Bytes containing the protection bits of the data bytes read (1...4 bytes)
The number L of protection bytes returned in the response is determined by the number N of data
bytes read from the card as follows:
L = 1 + INT(N/8) if N is not multiplies of 8
L = INT(N/8) if N is multiplies of 8
The arrangement of the protection bits in the PROT bytes is as follows:
PROT 1 PROT 2 ....
P
8
P
7
P
6
P
5
P
4
P
3
P
2
P
1
P
1
6
P
1
5
P
1
4
P
1
3
P
1
2
P
1
1
P
1
0
P
9
.. .. .. .. .. .. P
1
8
P
1
7
Px is the protection bit of BYTE x in the response data