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Renesas SH7781 User Manual

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14. Direct Memory Access Controller (DMAC)

Rev.1.00 Jan. 10, 2008 Page 722 of 1658
REJ09B0261-0100

: Non-sensitive period

CLKOUT

Bus cycle

DREQ (Rising edge)

DRAK (High-active)

DACK (High-active)

Acceptance started
Accepted after one cycle of CLKOUT
at the first rising edge of the divided-up DACK

1st acceptance

2nd acceptance

CPU

CPU

DMAC

Figure 14.14 Example 2 of DREQ Input Detection in Cycle Steal Mode Edge Detection

(Word Transfer in 8-Bit Bus Width, Longword Transfer in 8/16-Bit Bus Width, 16/32-Byte

Transfer in 8/16/32/64-Bit Bus Width: DACK of DMA1 Transfer Divided)

: Non-sensitive period

CLKOUT

Bus cycle

Address

DREQ (Rising edge)

DRAK (High-active)

DACK (High-active)

Acceptance started
Accepted after one cycle of CLKOUT
at the rising edge of DACK

1st acceptance

2nd acceptance

CPU

CPU

DMAC

Figure 14.15 Example 3 of DREQ Input Detection in Cycle Steal Mode Edge Detection

(Word Transfer in 8-Bit Bus Width, Longword Transfer in 8/16-Bit Bus Width, or 16/32-

Byte Transfer in 8/16/32/64-Bit Bus Width: DACK of DMA1 Transfer Is Connected)