Renesas HD6417641 - Figure 13.21 Example of DREQ Input Detection in Cycle Steal Mode Level Detection When DACK Is Divided to 4 by Idle Cycles

Section 13 Direct Memory Access Controller (DMAC)
Rev. 4.00 Sep. 14, 2005 Page 448 of 982
REJ09B0023-0400
CPU
DMAC write
Non-sensitive period
1st acceptance 2nd acceptance
3rd acceptance possible
Non-sensitive period
CPU
DMAC write
Non-sensitive period
1st acceptance 2nd acceptance
3rd acceptance possible
Non-sensitive period
CKIO
Bus cycle
DREQ
(Overrun 0,
high-level)
DACK
(High-active)
DREQ
(Overrun 1,
high-level)
DACK
(High-active)
CKIO
Bus cycle
Figure 13.21 Example of DREQ Input Detection in Cycle Steal Mode Level Detection
When DACK is Divided to 4 by Idle Cycles