Datasheet

Section 7 DMA Controller (DMAC)
Page 350 of 1384 R01UH0310EJ0500 Rev. 5.00
Sep 25, 2012
H8S/2426, H8S/2426R, H8S/2424 Group
7.5.2 Sequential Mode
Sequential mode can be specified by clearing the RPE bit in DMACR to 0. In sequential mode,
MAR is updated after each byte or word transfer in response to a single transfer request, and this is
executed the number of times specified in ETCR. One address is specified by MAR, and the other
by IOAR. The transfer direction can be specified by the DTDIR bit in DMACR.
Table 7.5 summarizes register functions in sequential mode.
Table 7.5 Register Functions in Sequential Mode
Function
Register DTDIR = 0 DTDIR = 1 Initial Setting Operation
23 0
MAR
Source
address
register
Destination
address
register
Start address of
transfer destination
or transfer source
Incremented/
decremented every
transfer
23 15 0
IOARH'FF
Destination
address
register
Source
address
register
Start address of
transfer source or
transfer destination
Fixed
015
ETCR
Transfer counter Number of transfers Decremented every
transfer; transfer
ends when count
reaches H'0000
MAR specifies the start address of the transfer source or transfer destination as 24 bits. MAR is
incremented or decremented by 1 or 2 each time a byte or word is transferred. IOAR specifies the
lower 16 bits of the other address. The 8 bits above IOAR have a value of H'FF.