Datasheet

Section 7 DMA Controller (DMAC)
R01UH0309EJ0500 Rev. 5.00 Page 327 of 1408
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
7.3.2 I/O Address Registers (IOARA and IOARB)
IOAR is a 16-bit readable/writable register that specifies the lower 16 bits of the source address
(transfer source address) or destination address (transfer destination address). The upper 8 bits of
the transfer address are automatically set to H'FF.
The DMA has four IOAR registers: IOAR_0A in channel 0 (channel 0A), IOAR_0B in channel 0
(channel 0B), IOAR_1A in channel 1 (channel 1A), and IOAR_1B in channel 1 (channel 1B).
Whether IOAR functions as the source address register or as the destination address register can
be selected by means of the DTDIR bit in DMACR.
IOAR is not incremented or decremented each time a data transfer is executed, so the address
specified by IOAR is fixed.
IOAR is not initialized by a reset or in standby mode.
IOAR can be used in short address mode but not in full address mode.