Section 11 Direct Memory Access Controller (DMAC)
Rev. 2.00 Mar 09, 2006 page 496 of 906
REJ09B0292-0200
11.3.5
Number of Bus Cycles
The number of states in the bus cycle when the DMAC is the bus master is controlled by the bus
state controller (BSC) just as it is when the CPU is the bus master. For details, see section 7, Bus
State Controller (BSC).
11.3.6
DMA Transfer Request Acknowledge Signal Output Timing
DMA transfer request acknowledge signal DACKn is output synchronous to the DMA address
output specified by the channel control register AM bit of the address bus. Normally, the
acknowledge signal becomes valid when DMA address output begins, and becomes invalid 0.5
cycles before the address output ends. (See figure 11.13.) The output timing of the acknowledge
signal varies with the settings of the connected memory space. The output timing of acknowledge
signals in the memory spaces is shown in figure 11.13.
Clock
DACKn
(Active high)
Address bus
CPU
DMAC
0.5 cycles
Figure 11.13 Example of DACKn Output Timing
Acknowledge Signal Output when External Memory Is Set as Ordinary Memory Space:
The timing at which the acknowledge signal is output is the same in the DMA read and write
cycles specified by the AM bit (figures 11.14 and 11.15). When DMA address output begins, the
acknowledge signal becomes valid; 0.5 cycles before address output ends, it becomes invalid. If a
wait is inserted in this period and address output is extended, the acknowledge signal is also
extended.
Summary of Contents for SH7616
Page 10: ...Rev 2 00 Mar 09 2006 page x of xxvi ...
Page 132: ...Section 2 CPU Rev 2 00 Mar 09 2006 page 106 of 906 REJ09B0292 0200 ...
Page 568: ...Section 12 16 Bit Free Running Timer FRT Rev 2 00 Mar 09 2006 page 542 of 906 REJ09B0292 0200 ...
Page 582: ...Section 13 Watchdog Timer WDT Rev 2 00 Mar 09 2006 page 556 of 906 REJ09B0292 0200 ...
Page 706: ...Section 16 Serial I O SIO Rev 2 00 Mar 09 2006 page 680 of 906 REJ09B0292 0200 ...
Page 820: ...Section 19 Pin Function Controller PFC Rev 2 00 Mar 09 2006 page 794 of 906 REJ09B0292 0200 ...
Page 932: ...Appendix D Package Dimensions Rev 2 00 Mar 09 2006 page 906 of 906 REJ09B0292 0200 ...
Page 935: ...SH7616 Hardware Manual ...