SH7751 Group, SH7751R Group
Section 14 Direct Memory Access Controller (DMAC)
R01UH0457EJ0301 Rev. 3.01
Page 531 of 1128
Sep 24, 2013
Figure 14.9 shows an example of DMA transfer timing in cycle steal mode. The transfer
conditions in this example are dual address mode and
DREQ
level detection.
CPU
CPU
DMAC
DMAC
CPU
DMAC
DMAC
CPU
CPU
CPU
DREQ
Bus cycle
Bus returned to CPU
Read
Write
Read
Write
Figure 14.9 Example of DMA Transfer in Cycle Steal Mode
Burst Mode:
In burst mode, once the DMAC has acquired the bus it holds the bus and transfers
data continuously until the transfer end condition is satisfied. Bus release by means of
BREQ
and
refresh requests conform to the DMAC burst mode transfer priority specification in bus control
register 1 (BCRL.DMABST). With
DREQ
low level detection in external request mode, however,
when
DREQ
is driven high the bus passes to another bus master after the end of the DMAC
transfer request that has already been accepted, even if the transfer end condition has not been
satisfied.
Figure 14.10 shows an example of DMA transfer timing in burst mode. The transfer conditions in
this example are single address mode and
DREQ
level detection (CHCRn.DS = 0, CHCRn.TM =
1).
CPU
DMAC
DMAC
DMAC
DMAC
DMAC
DMAC
CPU
CPU
CPU
DREQ
Bus cycle
Figure 14.10 Example of DMA Transfer in Burst Mode
Note: Burst mode can be set regardless of the transfer size. A 32-byte block transfer burst mode
setting can also be made.
Содержание SH7751 Group
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Страница 388: ...Section 12 Timer Unit TMU SH7751 Group SH7751R Group Page 334 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 800: ...Section 17 Smart Card Interface SH7751 Group SH7751R Group Page 746 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 848: ...Section 19 Interrupt Controller INTC SH7751 Group SH7751R Group Page 794 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 876: ...Section 20 User Break Controller UBC SH7751 Group SH7751R Group Page 822 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 1036: ...Section 22 PCI Controller PCIC SH7751 Group SH7751R Group Page 982 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
Страница 1152: ...Appendix C Mode Pin Settings SH7751 Group SH7751R Group Page 1098 of 1128 R01UH0457EJ0301 Rev 3 01 Sep 24 2013 ...
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