Техническая Спецификация для Atmel Evaluation Kit for AT32uC3A0512, 32-Bit AVR Microcontroller Atmel ATEVK1105 ATEVK1105
Модели
ATEVK1105
369
AT32UC3A
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
).
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 27-3.
Memory Connections for 6 External Devices
27.6.3
Connection to External Devices
27.6.3.1
Data Bus Width
A data bus width of 8, 16 or 32 bits can be selected for each chip select. This option is controlled
by the field DBW in MODE (Mode Register) for the corresponding chip select.
shows how to connect a 512K x 8-bit memory on NCS2.
shows how to
connect a 512K x 16-bit memory on NCS2.
shows two 16-bit memories connected
as a single 32-bit memory.
27.6.3.2
Byte Write or Byte Select Access
Each chip select with a 16-bit or 32-bit data bus can operate with one of two different types of
write access: byte write or byte select access. This is controlled by the BAT field of the MODE
register for the corresponding chip select.
NCS[0] - NCS[5]
NRD
NWE
A[25:0]
D[31:0]
D[31:0]
SMC
NCS5
NCS4
NCS3
NCS2
NCS1
NCS0
8 or 16 or 32
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Memory Enable
Output Enable
Output Enable
Write Enable
A[25:0]
D[31:0] or D[15:0] or
D[7:0]
32058K
AVR32-01/12