HD6417144 RENESAS [Renesas Technology Corp], HD6417144 Datasheet - Page 232

• Manufacturer Part Number: HD6417144
• Description: 32-Bit RISC Microcomputer SuperHTM RISC engine Family/SH7144 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

10. Direct Memory Access Controller (DMAC)
Address Modes:
• Single Address Mode
Rev.4.00 Mar. 27, 2008 Page 188 of 882
REJ09B0108-0400
In the single address mode, both the transfer source and destination are external; one 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 10.4 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.
Figure 10.4 Data Flow in Single Address Mode
This LSI
DMAC
External address bus
: Data flow
DREQ
DACK
External data bus
External device
with DACK
External
memory