PROFIBUS Controller SPC 4®-2 LF
44
C79000-G8976-C157-3
5.3 Indication
Queue
5.3.1 Description
Function
If the SPC 4-2 receives a frame, it enters the frame header in the indication queue
and
then
checks the free length in the queue (this is possible because one
segment must always remain free). If at least one segment (8 or 16 bytes) is free
(in addition to the special free segment), it continues reception and enters the data
in the queue as long as there is free memory available. When a request frame
(call) is received, the SPC 4-2 validates the frame header characters with the
values it has set in the SAP list. The structure is described Table 5-1 SAP List.
The indication queue is managed as a ring buffer with read (IND-RD) and write
(IND-WR) pointers. The SPC 4-2 is responsible for the write pointer and the FLC is
responsible for the read pointer.
The IND-WR-PRE pointer allows fast slave reactions (e.g. for DP). With a suitable
parameter assignment, an indication interrupt is generated after correct reception
of the request frame and not at the end of the next frame to another node.
Summary of Contents for SIMATIC NET SPC 4-2 LF
Page 9: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 9 Introduction 1 ...
Page 11: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 11 Functional Overview 2 ...
Page 14: ...PROFIBUS Controller SPC 4 2 LF 14 C79000 G8976 C157 3 ...
Page 15: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 15 Pin Assignment 3 ...
Page 18: ...PROFIBUS Controller SPC 4 2 LF 18 C79000 G8976 C157 3 ...
Page 19: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 19 Memory Assignment 4 ...
Page 32: ...PROFIBUS Controller SPC 4 2 LF 32 C79000 G8976 C157 3 ...
Page 33: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 33 FLC Interface 5 ...
Page 50: ...PROFIBUS Controller SPC 4 2 LF 50 C79000 G8976 C157 3 ...
Page 51: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 51 DP Interface 6 ...
Page 63: ...ASIC Interface PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 63 ASIC Interface 7 ...
Page 107: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 107 Asynchronous Interface 8 ...
Page 114: ...PROFIBUS Controller SPC 4 2 LF 114 C79000 G8976 C157 3 ...
Page 115: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 115 Synchronous Interface 9 ...
Page 125: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 125 Clock Pulses 10 ...
Page 128: ...PROFIBUS Controller SPC 4 2 LF 128 C79000 G8976 C157 3 ...
Page 129: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 129 Processor Interface 11 ...
Page 152: ...PROFIBUS Controller SPC 4 2 LF 152 C79000 G8976 C157 3 ...
Page 153: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 153 Technical Specifications 12 ...
Page 159: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 159 Package 13 ...
Page 165: ...Package PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 165 Figure 13 4 Tray Spezification ...
Page 166: ...PROFIBUS Controller SPC 4 2 LF 166 C79000 G8976 C157 3 ...
Page 168: ...PROFIBUS Controller SPC 4 2 LF 168 C79000 G8976 C157 3 ...
Page 169: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 169 Addresses 15 ...
Page 172: ...PROFIBUS Controller SPC 4 2 LF 172 C79000 G8976 C157 3 ...
Page 173: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 173 Appendix 16 ...
Page 178: ...PROFIBUS Controller SPC 4 2 LF 178 C79000 G8976 C157 3 ...