PROFIBUS Interface Center
SPC3
Page 28
V1.3
SPC3 Hardware Description
2003/04
Copyright (C) Siemens AG 2003. All rights reserved.
Address
Bit Position
Designation
RAM
Register
7
6
5
4
3
2
0
2AH
0
0
0
0
0
Set_
Slave_
Adr
Check_
Cfg
Set_
Prm
R_Aux_Puf_Sel
X1
X1
X1 See below for coding.
X1 Coding
0
Aux_Buffer1
1
Aux_Buffer2
Figure 6.2: Aux-Buffer Management
The user makes the configuration data (Get_Config) available in the Read_Cfg buffer for reading. The
Read_Cfg buffer must have the same length as the Cfg_buffer.
The Read_Input_Data telegram is operated from the Din buffer in the ‘D state’, and the Read_Output_Data
telegram is operated from the Dout buffer in the ‘U state.’
All buffer pointers are 8-bit segment addresses, because the SPC3 internally has only 8-bit address
registers. For a RAM access, SPC3 adds an 8-bit offset address to the segment address shifted by 3 bits
(result: 11-bit physical address). As regards the buffer start addresses, this results in an 8-byte graunularity
from this specification.
Summary of Contents for SPC3
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