ASIC Interface
PROFIBUS Controller SPC 4®-2 LF
C79000-G8976-C157-3
87
7.6
Memory Expansion to 3 Kbytes
The SPC 4-2 has an extra mode (can be set in mode register 3, see Section
7.1.11), in which the memory segment size of the internal RAM is increased from 8
to 16 bytes. With this mode, access to this RAM using the base pointer can
theoretically address up to 4 Kbytes instead of the previous maximum of 2 Kbytes
(although only 3 Kbytes are implemented.
8 Bit Basepointer-Register (Segmentadresse)
+ 8 Bit Adressbus
= 12 Bit RAM-Adresse
Figure 7-19
Memory Expansion to 3 Kbytes
When accessing data structures in this RAM in the new mode, it is therefore vital to
know how the data is shifted when there is a change to the 16-byte segment size.
The following rules apply to individual data structures:Data structures with 16 byte
segments
●
SAP List:
On the SPC4/SPC4-1 as well as on the SPC 4-2, this area begins at address
24 (018
h
). The SAP list is therefore not structured segment-oriented; in other
words, the bytes of all 64 SAPs follow on one after the other without gaps. This
structure was selected because this memory area of the internal RAM can be
accessed directly without needing to use a base pointer.
●
Indication blocks:
Each indication block begins at a segment boundary. Before the data, it
contains the response header and the request header making up a total of 8
bytes. The actual data are located in the next free segment. As a result, when
using 16 byte segments on the SPC 4-2, there is a gap of 8 bytes between the
headers and the data that follows. The data itself is stored without gaps.
●
Reply-On-Indication blocks:
Each of these blocks must begin at a segment boundary. In addition to the
data, each of these blocks begins with 2 bytes of header information. In
contrast to the indication blocks, the data follow on without a gap.
Содержание SIMATIC NET SPC 4-2 LF
Страница 9: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 9 Introduction 1 ...
Страница 11: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 11 Functional Overview 2 ...
Страница 14: ...PROFIBUS Controller SPC 4 2 LF 14 C79000 G8976 C157 3 ...
Страница 15: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 15 Pin Assignment 3 ...
Страница 18: ...PROFIBUS Controller SPC 4 2 LF 18 C79000 G8976 C157 3 ...
Страница 19: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 19 Memory Assignment 4 ...
Страница 32: ...PROFIBUS Controller SPC 4 2 LF 32 C79000 G8976 C157 3 ...
Страница 33: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 33 FLC Interface 5 ...
Страница 50: ...PROFIBUS Controller SPC 4 2 LF 50 C79000 G8976 C157 3 ...
Страница 51: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 51 DP Interface 6 ...
Страница 63: ...ASIC Interface PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 63 ASIC Interface 7 ...
Страница 107: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 107 Asynchronous Interface 8 ...
Страница 114: ...PROFIBUS Controller SPC 4 2 LF 114 C79000 G8976 C157 3 ...
Страница 115: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 115 Synchronous Interface 9 ...
Страница 125: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 125 Clock Pulses 10 ...
Страница 128: ...PROFIBUS Controller SPC 4 2 LF 128 C79000 G8976 C157 3 ...
Страница 129: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 129 Processor Interface 11 ...
Страница 152: ...PROFIBUS Controller SPC 4 2 LF 152 C79000 G8976 C157 3 ...
Страница 153: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 153 Technical Specifications 12 ...
Страница 159: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 159 Package 13 ...
Страница 165: ...Package PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 165 Figure 13 4 Tray Spezification ...
Страница 166: ...PROFIBUS Controller SPC 4 2 LF 166 C79000 G8976 C157 3 ...
Страница 168: ...PROFIBUS Controller SPC 4 2 LF 168 C79000 G8976 C157 3 ...
Страница 169: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 169 Addresses 15 ...
Страница 172: ...PROFIBUS Controller SPC 4 2 LF 172 C79000 G8976 C157 3 ...
Страница 173: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 173 Appendix 16 ...
Страница 178: ...PROFIBUS Controller SPC 4 2 LF 178 C79000 G8976 C157 3 ...