r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 409

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Figure 7.33 shows an example of single address transfer using the write data buffer function. In
this example, the CPU program area is in on-chip memory.
When the write data buffer function is activated, the DMAC recognizes that the bus cycle
concerned has ended, and starts the next operation. Therefore, DREQ pin sampling is started one
state after the start of the DMA write cycle or single address transfer.
7.5.12
The DMAC channel priority order is: channel 0 > channel 1, and channel A > channel B. Table
7.11 summarizes the priority order for DMAC channels.
Table 7.11 DMAC Channel Priority Order
Short Address Mode
Channel 0A
Channel 0B
Channel 1A
Channel 1B
Figure 7.33 Example of Single Address Transfer Using Write Data Buffer Function
Internal read signal
External address
Internal address
Multi-Channel Operation
DACK
RD
φ
DMA
read
DMA
single
Full Address Mode
Channel 0
Channel 1
CPU
read
Rev. 1.00 Sep. 19, 2008 Page 379 of 1342
DMA
single
Section 7 DMA Controller (DMAC)
Priority
High
Low
CPU
read
REJ09B0467-0100