Section 9 Direct Memory Access Controller (DMAC)
Rev. 5.00 May 29, 2006 page 273 of 698
REJ09B0146-0500
Address Modes:
•
Dual Address Mode
In the dual address mode, both the transfer source and destination are accessed (selectable) by
an address. The source and destination can be located externally or internally. The dual address
mode has (1) direct address transfer mode and (2) indirect address transfer mode.
(1) In the direct address transfer mode, DMA transfer requires two bus cycles because data is
read from the transfer source in a data read cycle and written to the transfer destination in a
data write cycle. At this time, transfer data is temporarily stored in the DMAC. In the
transfer between external memories as shown in figure 9.5, data is read to the DMAC from
one external memory in a data read cycle, and then that data is written to the other external
memory in a write cycle. Figures 9.6 to 9.8 show examples of the timing at this time.
Data buffer
Address b
u
s
Data b
u
s
Address b
u
s
Data b
u
s
Memory
Transfer source
module
Transfer destination
module
Memory
Transfer source
module
Transfer destination
module
SAR
DAR
Data buffer
SAR
DAR
The SAR value is an address, data is read from the transfer source module,
and the data is tempolarily stored in the DMAC.
First bus cycle
Second bus cycle
The DAR value is an address and the value stored in the data buffer in the
DMAC is written to the transfer destination module.
DMAC
DMAC
Figure 9.5 Operation in the Direct Address Mode in the Dual Address Mode
Summary of Contents for SH7706 Series
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Page 160: ...Section 5 Cache Rev 5 00 May 29 2006 page 112 of 698 REJ09B0146 0500 ...
Page 370: ...Section 11 Watchdog Timer WDT Rev 5 00 May 29 2006 page 322 of 698 REJ09B0146 0500 ...
Page 554: ...Section 17 Pin Function Controller PFC Rev 5 00 May 29 2006 page 506 of 698 REJ09B0146 0500 ...
Page 576: ...Section 18 I O Ports Rev 5 00 May 29 2006 page 528 of 698 REJ09B0146 0500 ...
Page 746: ...Index Rev 5 00 May 29 2006 page 698 of 698 REJ09B0146 0500 ...
Page 749: ...SH7706 Group Hardware Manual ...