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TMP92CZ26A
92CZ26A-204
3.9 External Memory Extension Function (MMU)
This is MMU function which can expand program/data area to 3.1G bytes by having 4-type
local area.
The recommendation address memory map is shown in
Figure 3.9.1.
However, when total capacity of used memory is less than 16M bytes, please refer to section of
Memory controller. Setting of register in MMU is not necessary.
An area which can be set as BANK is called LOCAL-area. Since the address for LOCAL area
is fixed, it cannot be changed.
And, area that cannot be set as BANK is called COMMON-area.
Basically one series of program should be closed within one bank. Please don’t jump to the
same LOCAL-area in the different bank directly by JP instruction and so on. Refer to the
examples as follows.
TMP92CZ26A has following external pins to connect external memory-LSI.
Address bus : EA28, EA27, EA26, EA25, EA24 and A23 to A0
Chip Select :
0CS
to 3CS ,
CSXA
to
CSXB
,
CSZA
to
CSXD
,
SDCS
,
CE0ND
and
CE1ND
Data bus : D15 to D0
3.9.1 Recommended memory map
Figure 3.9.1 shows one of recommendation address memory map. It can be expanded to
maximum memory size.
Figure 3.9.3 also shows one of recommendation address memory map. It’s for a simple
memory system like internal Boot-ROM with NAND-Flash and SDRAM.