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Rev. 5.00, 09/03, page 355 of 760
Memory
Transfer source
module
Transfer destination
module
SAR3
DAR3
Data
buffer
Temporary
buffer
D
M
A
C
When the value in SAR3 is an address, the memory data is read and
the value is stored in the temporary buffer. The value to be read must
be 32 bits since it is used for the address. If data bus connected to an
external memory space is 16 bits wide, two bus cycles are necessary.
Memory
Transfer source
module
Data bus
Address bus
Transfer destination
module
SAR3
DAR3
Data
buffer
Temporary
buffer
D
M
A
C
Memory
Transfer source
module
Data bus
Address bus
Transfer destination
module
SAR3
DAR3
Data
buffer
Temporary
buffer
D
M
A
C
First and second bus cycles
When the value in the temporary buffer is an address, the data is read
from the transfer source module to the data buffer.
Third bus cycle
Fourth bus cycle
When the value in SAR3 is an address, the value in the data buffer is
written to the transfer source module.
Note: This example shows memory, the transfer source module, and
the transfer destination module; in practice, any module can be
connected in the addressing space.
Data bus
Address bus
Figure 11.7 Indirect Address Operation in Dual Address Mode
(When External Memory Space has a 16-Bit Width)