Siemens ERTEC200 사용자 설명서

 

 

128 Byte physical 
Note2 

  

Steuer-Register for external Memory-Interface
64 Byte physical 
Note2 

 

16 Byte physikalisch 
Note2 

 

 

1.   Access to IRT registers and KRAM should only occur in the address areas indicated above (first 2 Mbytes). An access to areas 
within the 2 Mbytes that are not occupied by the IRT registers and KRAM result in undefined access (acknowledgement timeout). The 
read or written data are not valid. While the 2-Mbyte areas are mirrored within the 8-Mbyte physical address area, different access types 
are used: 

¾ 

2-4-Mbyte area for unaligned consistent 16-bit accesses to IRT 

¾ 

4-6-Mbyte area for unaligned consistent 32-bit accesses to IRT 

¾ 

6-8 Mbytes is not supported (supplies undefined values) 

The 8-Mbyte address area is mirrored 32 times within the 256 Mbytes. 
 
2.   Memory areas are mirrored according to the following formula: 
 
 

   

 

Memory size  

 N 

= 

-------------------------------------------- 

  

 

    Physical memory size 

 
Physical memory size is limited to values of 2

n 

 (2, 4, 8, ... 128, 256 etc.) 

 
Example: The physical memory size of the watchdog is 28 bytes. However, 32 bytes are taken for calculating the number of mirrorings 
N. In this case, the number of mirrorings N = 8. Access to the 4 unused bytes does not result in an acknowledgement timeout, but the 
read or written values are undefined. 

 

 

Copyright © Siemens AG 2007. All rights reserved.                  

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