HD6432670 Hitachi, HD6432670 Datasheet - Page 377

• Manufacturer Part Number: HD6432670
• Description: (HD64F267x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

This LSI has a built-in four-channel external bus transfer DMA controller (EXDMAC). The
EXDMAC can carry out high-speed data transfer, in place of the CPU, to and from external
devices and external memory with a DACK (DMA transfer notification) facility.
8.1
Figure 8.1 shows a block diagram of the EXDMAC.
EDMA260A_010020020400
Direct specification of 16-Mbyte address space
Selection of byte or word transfer data length
Maximum number of transfers: 16M (16,777,215)/infinite (free-running)
Selection of dual address mode or single address mode
Selection of cycle steal mode or burst mode as bus mode
Selection of normal mode or block transfer mode as transfer mode
Two kinds of transfer requests: external request and auto-request
An interrupt request can be sent to the CPU at the end of the specified number of transfers.
Repeat area designation function:
Operation in parallel with internal bus master:
Acceptance of a transfer request and the start of transfer processing can be reported to an
external device via the
Module stop mode can be set.
Features
Section 8 EXDMA Controller
pin.
Rev. 2.0, 04/02, page 331 of 906