AET63 Reference Manual
version 1.8 September 2006
Advanced Card Systems Ltd.
Page 14 of 29
Within the command and response transmission only ASCII characters representing the hexadecimal (hex)
digits 0...F are used. Each byte of a command or response is split into its upper and lower halfbyte (nibble).
For each halfbyte is transmitted the ASCII character representing the respective hex digit value. For
example, to transmit the data byte 3A
H
, two bytes are actually sent on the interface, namely, 33
H
(ASCII code
for '3') followed by 41
H
(ASCII code for 'A'):
Data byte value
3A
H
Transmitted values
33
H
= '3'
41
H
= 'A'
The following example shows the transmission of a command with instruction code A2
H
and one data byte
with the value 3D
H
. The command has the following structure:
byte
1
2
3
4
5
Header
Instruction
Data length
Data
Checksum
01
H
A2
H
01
H
3D
H
9F
H
This command is transmitted on the serial interface in 12 bytes as follows:
byte
1
2
3
4
5
6
7
8
9
10
11
12
STX
'0'
'1'
'A'
'2'
'0'
'1'
'3'
'D'
'9'
'F'
ETX
02
H
30
H
31
H
41
H
32
H
30
H
31
H
33
H
44
H
39
H
46
H
03
H
For the representation of the hex halfbyte values as the corresponding ASCII characters in commands, the
AET63 accepts both upper case characters 'A' ... 'F' (41
H
... 46
H
) and lower case characters 'a' ... 'f' (61
H
...
66
H
):
byte
1
2
3
4
5
6
7
8
9
10
11
12
STX
'0'
'1'
'A'
'2'
'0'
'1'
'3'
'D'
'9'
'F'
ETX
02
H
30
H
31
H
41
H
32
H
30
H
31
H
33
H
44
H
39
H
46
H
03
H
... is equivalent to:
byte
1
2
3
4
5
6
7
8
9
10
11
12
STX
'0'
'1'
'a'
'2'
'0'
'1'
'3'
'd'
'9'
'f'
ETX
02
H
30
H
31
H
61
H
32
H
30
H
31
H
33
H
64
H
39
H
66
H
03
H
In its response messages, the AET63 uses upper case characters 'A' ... 'F'.
