
Rev. 6.0, 07/02, page 502 of 986
Bit 19—
DREQ
DREQ
DREQ
DREQ
Select (DS): Specifies either low level detection or falling edge detection as the
sampling method for the
DREQ
pin used in external request mode.
In normal DMA mode, this bit is valid only in CHCR0 and CHCR1. In DDT mode, it is valid in
CHCR0–CHCR3.
Bit 19: DS
Description
0
Low level detection
(Initial value)
1
Falling edge detection
Note:
Level detection burst mode when TM = 1 and DS = 0
Edge detection burst mode when TM = 1 and DS = 1
Bit 18—Request Check Level (RL): Selects whether the DRAK signal (that notifies an external
device of the acceptance of
DREQ
) is an active-high or active-low output.
In normal DMA mode, this bit is valid only in CHCR0 and CHCR1. In DDT mode, this bit is
invalid.
Bit 18: RL
Description
0
DRAK is an active-high output
(Initial value)
1
DRAK is an active-low output
Bit 17—Acknowledge Mode (AM): In dual address mode, selects whether DACK is output in the
data read cycle or write cycle. In single address mode, DACK is always output regardless of the
setting of this bit.
In normal DMA mode, this bit is valid only in CHCR0 and CHCR1. In DDT mode, this bit is
valid for CHCR1 to CHCR3 in the SH7750. In the SH7750S, this bit is valid for CHCR0 to
CHCR3. (DDT mode:
TDACK
)
Bit 17: AM
Description
0
DACK is output in read cycle
(Initial value)
1
DACK is output in write cycle
Summary of Contents for SH7750 series
Page 106: ...Rev 6 0 07 02 page 56 of 986 ...
Page 144: ...Rev 6 0 07 02 page 94 of 986 ...
Page 242: ...Rev 6 0 07 02 page 192 of 986 ...
Page 270: ...Rev 6 0 07 02 page 220 of 986 ...
Page 360: ...Rev 6 0 07 02 page 310 of 986 ...
Page 538: ...Rev 6 0 07 02 page 488 of 986 ...
Page 706: ...Rev 6 0 07 02 page 656 of 986 ...
Page 752: ...Rev 6 0 07 02 page 702 of 986 ...
Page 780: ...Rev 6 0 07 02 page 730 of 986 ...
Page 822: ...Rev 6 0 07 02 page 772 of 986 ...
Page 986: ...Rev 6 0 07 02 page 936 of 986 ...
Page 1030: ...Rev 6 0 07 02 page 980 of 986 ...
Page 1036: ...Rev 6 0 07 02 page 986 of 986 ...