HD6417034B RENESAS [Renesas Technology Corp], HD6417034B Datasheet - Page 227

• Manufacturer Part Number: HD6417034B
• Description: 32-Bit RISC Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

9.3.4
The DMAC supports the transfers shown in table 9.5. It can operate in single address mode or dual
address mode, which are defined by how many bus cycles the DMAC takes to access the transfer
source and transfer destination. The actual transfer operation timing varies with the bus mode. The
DMAC has two bus modes: cycle-steal mode and burst mode.
Table 9.5
Source
External device with
DACK
External memory
Memory-mapped external
device
On-chip memory
On-chip supporting
module
Single: Single address mode
Dual: Dual address mode
Address Modes:
Single Address Mode
In single address mode, both the transfer source and destination are external; one (selectable) is
accessed by a DACK signal while the other is accessed by an address. In this mode, the
DMAC performs the DMA transfer in 1 bus cycle by simultaneously outputting a transfer
request acknowledge DACK signal to one external device to access it while outputting an
address to the other end of the transfer. Figure 9.6 shows an example of a transfer between an
external memory and an external device with DACK in which the external device outputs data
to the data bus while that data is written in external memory in the same bus cycle.
DMA Transfer Types
Supported DMA Transfers
External
Device with
DACK
Not available
Single
Single
Not available
Not available
External
Memory
Single
Dual
Dual
Dual
Dual
Section 9 Direct Memory Access Controller (DMAC)
Memory-
Mapped
External
Device
Single
Dual
Dual
Dual
Dual
Destination
Rev. 7.00 Jan 31, 2006 page 201 of 658
Not available
On-Chip
Memory
Dual
Dual
Dual
Dual
REJ09B0272-0700
On-Chip
Supporting
Module
Not available
Dual
Dual
Dual
Dual