Motorola DSP56012 - Manual (Page 68)

3-8 DSP56012 User’s Manual MOTOROLA
Memory, Operating Modes, and Interrupts
DSP56012 Data and Program Memory Maps
Figure 3-4 Memory Maps for PEA = 1, PEB = 1
3.3.2 Dynamic Switch of Memory Configurations
The internal memory configuration is altered by re-mapping RAM modules from X
and Y data memories into program memory space and vice versa. Data contents of
the switched RAM modules are preserved.
The memory can be dynamically switched from one configuration to another by
changing the PEA and PEB bits in the OMR. The address ranges that are directly
affected by the switch operation are P:$0200–$0AFF, X:$0A00–$0FFF and
Y:$0E00–$10FF (see Figure 3-1, Figure 3-2, Figure 3-3, and Figure 3-4). The memory
switch can be accomplished provided that the affected address ranges are not being
accessed during the instruction cycle in which the switch operation takes place.
Specifically, the following two conditions must be observed for trouble-free dynamic
switching:
• No accesses to or from X:$0A00–$0FFF or Y:$0E00–$10FF are allowed during
the switch cycle.