r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 394

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

Section 7 DMA Controller (DMAC)
7.5.9
(1)
Figure 7.18 shows a transfer example in which TEND output is enabled and byte-size short
address mode transfer (sequential/idle/repeat mode) is performed from external 8-bit, 2-state
access space to internal I/O space.
A byte or word transfer is performed for a single transfer request, and after the transfer, the bus is
released. While the bus is released, one or more bus cycles are executed by the CPU or DTC.
In the transfer end cycle (the cycle in which the transfer counter reaches 0), a one-state DMA dead
cycle is inserted after the DMA write cycle.
In repeat mode, when TEND output is enabled, TEND output goes low in the transfer end cycle.
Rev. 1.00 Sep. 19, 2008 Page 366 of 1270
REJ09B0466-0100
Address bus
Short Address Mode
TEND
HWR
LWR
RD
DMA Transfer (Dual Address Mode) Bus Cycles
φ
Bus release
Figure 7.18 Example of Short Address Mode Transfer
DMA
read
DMA
write
Bus release
DMA
read
DMA
write
Bus release
DMA
read
Last transfer
cycle
DMA
write
DMA
dead
Bus
release