Technical data

8.3 User Memory Organization in the CPU 928B
Depending on the memory submodule you are using, the user memory
consists of the memory area from 0000H to 7FFFH. When you load
the blocks of the user program, they are stored in any order (addresses
in ascending order).
"Alternative loading" of the
data blocks
There are alternative methods of loading DB/DX data blocks
depending on the setting in system data word RS 144:
The default is that the data blocks are first loaded into the user
memory. Only when this has been filled are the data blocks stored in
internal DB RAM (8000H to DD7FH). You can reverse this order by
setting bit 0 in RS 144 ("alternative loading").
Memory information With the online function MEM CONF (memory configuration) you
can obtain the address (hexadecimal) of the memory cell containing
the block end operation of the last block in the memory submodule
which then tells you the occupation of the RAM submodule.
Block management When you correct blocks, the "old" block is declared invalid in the
memory and a new block is set up. This also applies when you delete
blocks; the blocks are not really deleted in the memory, but simply
declared invalid. Gaps created when blocks are deleted are seen as
free memory locations and used again when new blocks are loaded.
Compress memory Using the COMPRESS MEMORY online function you can create
memory space for new blocks. This function optimizes the memory
occupation by deleting blocks marked as invalid and shifting valid
blocks together. The shifting is separate for the memory submodule
and internal RAM module (see Section 11.2.2).
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User Memory Organization in the CPU 928B
CPU 928B Programming Guide
C79000-B8576-C898-01
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