3.2. Memory map options

Supporting several memory configurations and operating systems requires some configurability of the memory map.

CFGBRIDGEMEMMAP

This signal defines the memory regions occupied by AHB bridge1 and AHB bridge 2. Accesses to memory regions that are not decoded on-chip are presented to one of the off-chip bridges. If an external device does not acknowledge the request, a bus fault is generated.

MPMCnSMC

This signal defines the controller that is used to access static memory. If HIGH, the MPMC controls static memory. If LOW, the SMC controls static memory.

REMAPSTATIC

When HIGH the region at 0x00000000 is mapped to SSMC chip select 7 if MPMCnSMC is LOW or MPMC chip select 1 if MPMCnSMC is HIGH.

REMAPEXTERNAL

When HIGH and REMAPSTATIC is LOW and REMAPMPMCCS5 is LOW, then the region at 0x00000000 is mapped externally to the ARM926PXP development chip.

REMAPMPMCCS5

When HIGH and REMAPSTATIC is LOW, then the region at 0x00000000 is mapped to the MPMC dynamic memory chip select 1 (nMPMCDYCS1).

The control logic is shown in Figure 3.5.

Figure 3.5. Memory control signals

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