3.3.4. Memory aliasing at reset

Under normal operation, the baseboard has dynamic memory located at 0x0. In order to run the boot code after a reset however, non-volatile memory must be remapped to the boot address.

Remapping is done by modifying the static memory controller chip select signals that connect to the memory devices. Figure 3.15 shows a simplified equivalent diagram of the remapping logic circuitry.

At reset, the REMAP signal from the system controller is HIGH. The DMCS0 signal that is normally generated by accesses to memory region 0x00000000-0x0FFFFFFF is disabled and routed to static memory:

See Remapping of boot memory.

Note

If the size of the physical memory selected is less than the address range of 0x00000000-0x0FFFFFFF, the physical memory is aliased and repeated to fill the address space.

Figure 3.15. Boot memory remap logic

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