Software Overview 2-2
I/O Data
The I/O data from the AS-Interface network can be devided into two categories:
• Digital I/O
• Analog I/O
Digital I/O
Digital I/O data is available in the Input and Output Data areas. The data can be presented in two ways;
Nibble and Byte. In Byte mode, each byte in the I/O area represents a slave on the nework, while in
Nibble mode each byte holds data for two slaves.
The way data is presented can be set either using mailbox commands or via the onboard Configuration
Interface.
• Data representation in byte mode:
In this mode, the data for each slave is located in the lower nibble of each byte.
• Data representation in nibble mode:
(Even slaves = high nibble, Odd slaves = low nibble)
Analog I/O
• Slave profiles 7.1 and 7.2
Values are read/written by the application software using I/O data directly in the input / output
areas. The application has to access each slave according to the special sequence defined in the
specification for analog slaves, profiles 7.1 and 7.2.
• Slave profiles 7.3 and 7.4
Analog values are be read/written by the application software using dedicated mailbox com-
mands; the number of slaves supported is 32 and starts with slave address 1 to 31.
The application is responsible for polling the detected analog 7.3 and 7.4 profile slaves when new
data is required.
Offset
Slave no.
Byte 0
0
1
2
3
4
5
6
7
Byte 8
8
9
10
11
12
13
14
15
Byte 16
16
17
18
19
20
21
22
23
Byte 24
24
25
26
27
28
29
30
31
Byte 32
-
33
34
35
36
37
38
39
Byte 40
40
41
42
43
44
45
46
47
Byte 48
48
49
50
51
52
53
54
55
Byte 56
56
57
58
59
60
61
62
63
Offset
Slave no.
Byte 0
1 / 0
3 / 2
5 / 4
7 / 6
9 / 8
11 / 10
13 / 12
15 / 14
Byte 8
17 / 16
19 / 18
21 / 20
23 / 22
25 / 24
27 / 26
29 / 28
31 / 30
Byte 16
33 / -
35 / 34
37 / 36
39 / 38
41 / 40
43 / 42
45 / 44
47 / 46
Byte 24
49 / 48
51 / 50
53 / 52
55 / 54
57 / 56
59 / 58
61 / 60
63 / 62
