Datasheet

SAM9261 [DATASHEET]

Atmel-6062O-ATARM-SAM9261-Datasheet_21-Jun-16

156

20.6 External Memory Mapping

The SMC provides up to 26 address lines, A[25:0]. This allows each chip select line to address up to 64 Mbytes of

memory.

If the physical memory device connected on one chip select is smaller than 64 Mbytes, it wraps around and

appears to be repeated within this space. The SMC correctly handles any valid access to the memory device

within the page (see Figure 20-2).

A[25:0] is only significant for 8-bit memory, A[25:1] is used for 16-bit memory, A[25:2] is used for 32-bit memory.

Figure 20-2. Memory Connections for Eight External Devices

NRD

NWE

A[25:0]

D[31:0]

8 or 16 or 32

Memory Enable

Output Enable

Write Enable

A[25:0]

D[31:0] or D[15:0] or

D[7:0]

NCS3

NCS0

NCS1

NCS2

NCS7

NCS4

NCS5

NCS6

NCS[0] - NCS[7]

SMC