r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 436

• Manufacturer Part Number: r4f2426
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Section 8 EXDMA Controller (EXDMAC)
8.4
8.4.1
The transfer modes of the EXDMAC are summarized in table 8.2.
Table 8.2
The transfer mode can be set independently for each channel.
In normal transfer mode, a one-byte or one-word transfer is executed in response to one transfer
request. With auto requests, burst or cycle steal transfer mode can be set. In burst transfer mode,
continuous, high-speed transfer can be performed until the specified number of transfers have
been executed or the transfer enable bit is cleared to 0.
Rev. 1.00 Sep. 19, 2008 Page 408 of 1270
REJ09B0466-0100
Dual
address
mode
Single
address
mode
Operation
Transfer Modes
Normal
transfer
mode
Block
transfer
mode
• Direct data transfer to/from external device using
• Above transfer mode can be specified in addition to
• One transfer possible in one bus cycle
(Transfer mode variations are the same as in dual
address mode.)
EXDMAC Transfer Modes
EDACK pin instead of source or destination address
register
address register setting
Transfer Mode
Auto request mode
• Burst/cycle steal
External request
mode
• Cycle steal mode
External request
mode
• Burst transfer of
• Block size: 1 to
mode
specified block
size for a single
transfer request
256 bytes or
words
Transfer
Origin
Auto
request
External
request
External
request
Number of
Transfers
1 to
16,777,215
or no
specification
1 to 65,535
or no
specification
Source
EDSAR
EDSAR/
EDACK
Address Registers
Destination
EDDAR
EDACK/
EDDAR