Section 10 Direct Memory Access Controller (DMAC)
Rev. 0.50 May 18, 2006 Page 414 of 1588
REJ09B0313-0050
Figure 10.8 shows an example of DMA transfer timing in single address mode.
Address output to external memory space
Select signal to external memory space
Select signal to external memory space
Data output from external device with DACK
DACK signal (active-low) to external device with DACK
Write strobe signal to external memory space
Address output to external memory space
Data output from external memory space
DACK signal (active-low) to external device with DACK
Read strobe signal to external memory space
(a) External device with DACK
→
External memory space (normal memory)
(b) External memory space (normal memory)
→
External device with DACK
CK
A25 to A0
D31 to D0
DACKn
CSn
WEn
CK
A25 to A0
D31 to D0
DACKn
CSn
RD
Figure 10.8 Example of DMA Transfer Timing in Single Address Mode
(2) Bus
Modes
There are two bus modes; cycle steal and burst. Select the mode by the TB bits in the channel
control registers (CHCR).
(a) Cycle Steal Mode
•
Normal mode
In normal mode of cycle steal, the bus mastership is given to another bus master after a one-
transfer-unit (byte, word, longword, or 16-byte unit) DMA transfer. When another transfer
request occurs, the bus mastership is obtained from another bus master and a transfer is
performed for one transfer unit. When that transfer ends, the bus mastership is passed to
another bus master. This is repeated until the transfer end conditions are satisfied.
The cycle-steal normal mode can be used for any transfer section; transfer request source,
transfer source, and transfer destination.
Figure 10.9 shows an example of DMA transfer timing in cycle-steal normal mode. Transfer
conditions shown in the figure are;
Summary of Contents for Single-Chip Microcomputer SH7203
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Page 52: ...Section 1 Overview Rev 0 50 May 18 2006 Page 22 of 1588 REJ09B0313 0050 ...
Page 98: ...Section 2 CPU Rev 0 50 May 18 2006 Page 68 of 1588 REJ09B0313 0050 ...
Page 128: ...Section 4 Clock Pulse Generator CPG Rev 0 50 May 18 2006 Page 98 of 1588 REJ09B0313 0050 ...
Page 200: ...Section 6 Interrupt Controller INTC Rev 0 50 May 18 2006 Page 170 of 1588 REJ09B0313 0050 ...
Page 242: ...Section 8 Cache Rev 0 50 May 18 2006 Page 212 of 1588 REJ09B0313 0050 ...
Page 400: ...Section 9 Bus State Controller BSC Rev 0 50 May 18 2006 Page 370 of 1588 REJ09B0313 0050 ...
Page 696: ...Section 13 Watchdog Timer WDT Rev 0 50 May 18 2006 Page 666 of 1588 REJ09B0313 0050 ...
Page 726: ...Section 14 Realtime Clock RTC Rev 0 50 May 18 2006 Page 696 of 1588 REJ09B0313 0050 ...
Page 876: ...Section 17 I2 C Bus Interface 3 IIC3 Rev 0 50 May 18 2006 Page 846 of 1588 REJ09B0313 0050 ...
Page 1054: ...Section 21 D A Converter DAC Rev 0 50 May 18 2006 Page 1024 of 1588 REJ09B0313 0050 ...
Page 1294: ...Section 24 LCD Controller LCDC Rev 0 50 May 18 2006 Page 1264 of 1588 REJ09B0313 0050 ...
Page 1386: ...Section 26 I O Ports Rev 0 50 May 18 2006 Page 1356 of 1588 REJ09B0313 0050 ...
Page 1512: ...Section 30 List of Registers Rev 0 50 May 18 2006 Page 1482 of 1588 REJ09B0313 0050 ...
Page 1598: ...Section 31 Electrical Characteristics Rev 0 50 May 18 2006 Page 1568 of 1588 REJ09B0313 0050 ...
Page 1606: ...Appendix Rev 0 50 May 18 2006 Page 1576 of 1588 REJ09B0313 0050 ...
Page 1618: ...Rev 0 50 May 18 2006 Page 1588 of 1588 REJ09B0313 0050 ...
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