SH7080 Datasheet, PDF (441/1644 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperH™ RISC engine Family

Section 10 Direct Memory Access Controller (DMAC)
Section 10 Direct Memory Access Controller (DMAC)
This LSI includes the 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, on-chip
memory, memory-mapped external devices, and on-chip peripheral modules.
10.1 Features
• Four channels (external requests can be received)
• 4-Gbyte physical address space
• Data transfer unit is selectable: Byte, word (2 bytes), longword (4 bytes), and 16 bytes
(longword × 4)
• Maximum transfer count: 16,777,216 transfers
• Address mode: Dual address mode or single address mode can be selected.
• Transfer requests:
External request, on-chip peripheral module request, or auto request can be selected.
• Selectable bus modes:
Cycle steal mode (normal mode and intermittent mode) or burst mode can be selected.
• Selectable channel priority levels:
The channel priority levels are selectable between fixed mode and round-robin mode.
• Interrupt request: An interrupt request can be generated to the CPU after transfers end by the
specified counts.
• External request detection: There are following four types of DREQ input detection.
 Low level detection
 High level detection
 Rising edge detection
 Falling edge detection
• Transfer request acknowledge signal:
Active levels for DACK can be set independently.
DMAS301A_010020030200
Rev. 3.00 May 17, 2007 Page 383 of 1582
REJ09B0181-0300