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CHAPTER 16 DMA CONTROLLER (DMAC)
Table 16.3-3 Specifiable Transfer Addresses (for Demand Transfer 2-Cycle Transfer)
Transfer source address
•
For a demand transfer, be sure to set an external area address for the transfer source or
transfer destination or both. Since DMA transfer is adjusted to the external bus timing in
demand transfer mode, access to external areas is always needed.
•
Since the SDRAM area is not supported as a transfer source/transfer destination during
demand transfer, this area cannot be set.
■ Demand Transfer Fly-by Transfer
A demand transfer fly-by transfer has the same features as a 2-cycle transfer except that the
transfer area can only be external areas, and the transfer unit is read (memory → I/O) or write (I/
O → memory) only.
Table 16.3-4 shows the specifiable transfer addresses.
Table 16.3-4 Specifiable Transfer Addresses (for Demand Transfer Fly-by Transfer)
Transfer source addressing
Specification not required (invalid)
348
External area
External area
External area
Built-in IO
Built-in RAM
Direction
Transfer destination
=>
External area
=>
=>
Built-in RAM
=>
External area
=>
External area
Direction
Transfer destination addressing
None
address
Built-in IO
External area
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