HD6417615 Hitachi Semiconductor, HD6417615 Datasheet - Page 515

• Manufacturer Part Number: HD6417615
• Description: Hardware Manual
• Manufacturer: Hitachi Semiconductor

Transfer Width
Transfer bus mode
Transfer address mode
500
Figure 11.34 DREQn Pin Input Detection Timing in Cycle-Steal Mode with Edge Detection
Clock
Bus cycle
DREQn
(Rising-edge
detection)
DACKn
(Active high)
1st
acceptance
(Active high)
(Active high)
CPU
Bus cycle
DREQn
DACKn
Clock
Figure 11.33 DREQn/DACKn Handshaking
Byte/Word/Longword
Cycle-steal mode
Dual/single mode
CPU
1st
acceptance
2nd
acceptance
DMAC
CPU
DMAC
Blind zone
CPU
DREQn Detection
Method
DACKn output timing
Bus cycle
CPU
2nd
acceptance
Requests acceptable
DMAC
CPU
3rd
acceptance
CPU
Edge Detection
Read DACK/write
DACK
Basic bus cycle
DMAC
DMAC