r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 475

• Manufacturer Part Number: r4f2426
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

(4)
In block transfer mode, transfer of one block is performed continuously in the same way as in
burst mode. The timing of the start of the next block transfer is the same as in normal transfer
mode.
If a transfer request is generated for another channel, an EXDMA cycle for the other channel is
generated before the next block transfer.
The EDREQ pin sensing timing is different for low level sensing and falling edge sensing. The
same applies to transfer request acceptance and transfer start timing.
Figures 8.39 to 8.44 show operation timing examples for various conditions.
Figure 8.38 External Request/Cycle Steal Mode/Normal Transfer Mode Contention
φ pin
Original
channel
EDREQ
Original
channel
EDRAK
Bus cycle
Other
channel
EDREQ
Other
channel
EDRAK
External Request/Cycle Steal Mode/Block Transfer Mode
EXDMA transfer
with Another Channel/Dual Address Mode/Low Level Sensing
cycle
Bus release
3 cycles
EXDMA
read
EXDMA
write
1 cycle
Bus
release
Rev. 1.00 Sep. 19, 2008 Page 447 of 1270
Other channel
transfer cycle
Section 8 EXDMA Controller (EXDMAC)
1 cycle
Bus
release
EXDMA
read
REJ09B0466-0100
EXDMA
write