HD6417034B RENESAS [Renesas Technology Corp], HD6417034B Datasheet - Page 205

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

9.1
The SuperH microcomputer chip includes a four-channel direct memory access controller
(DMAC). The DMAC can be used in place of the CPU to perform high speed transfers between
external devices that have DACK (transfer request acknowledge signal), external memory,
memory-mapped external devices, on-chip memory, and on-chip supporting modules (excluding
the DMAC itself). Using the DMAC reduces the burden on the CPU and increases overall
operating efficiency.
9.1.1
The DMAC has the following features.
Four channels
Four Gbytes of address space in the architecture
Byte or word selectable as data transfer unit
65536 transfers (maximum)
Single address mode transfers (channels 0 and 1): Either the transfer source or transfer
destination (peripheral device) is accessed by a DACK signal (selectable) while the other is
accessed by address. One transfer unit of data is transferred in each bus cycle.
Device combinations for which transfer is possible:
Dual address mode transfer (channels 0–3): Both the transfer source and transfer destination
are accessed by address. One transfer unit of data is transferred in 2 bus cycles.
Device combinations for which transfer is possible:
Section 9 Direct Memory Access Controller (DMAC)
External device with DACK and memory-mapped external device (including external
memories)
External device with DACK and memory-mapped external memory
Two external memories
External memory and memory-mapped external device
Two memory-mapped devices
External memory and on-chip memory
Memory-mapped external device and on-chip supporting module (excluding the DMAC)
External memory and on-chip memory
Memory-mapped external device and on-chip supporting module (excluding the DMAC)
Two on-chip memories
Features
Overview
Section 9 Direct Memory Access Controller (DMAC)
Rev. 7.00 Jan 31, 2006 page 179 of 658
REJ09B0272-0700