Datasheet

Section 7 DMA Controller (DMAC)
R01UH0309EJ0500 Rev. 5.00 Page 349 of 1408
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
Figure 7.2 shows the transfer areas for activating the DTC with a channel 0A transfer end interrupt
request, and reactivating channel 0A. The address register and count register areas are set again
during the first DTC transfer, then the control register area is set again during the second DTC
chain transfer. When re-setting the control register area, perform masking by setting bits in
DMAWER to prevent modification of the contents of other channels.
DTC
MAR_0AH
MAR_0AL
IOAR_0A
ETCR_0A
MAR_0BH
MAR_0BL
IOAR_0B
ETCR_0B
MAR_1AH
MAR_1AL
IOAR_1A
ETCR_1A
MAR_1BH
MAR_1BL
IOAR_1B
ETCR_1B
DMATCR
DMACR_0B
DMACR_1B
DMAWER
DMACR_0A
DMACR_1A
DMABCR
Second transfer area
using chain transfer
First transfer area
Figure 7.2 Areas for Register Re-Setting by DTC (Channel 0A)
Writes by the DTC to bits 15 to 12 (FAE and SAE) in DMABCR are invalid regardless of the
DMAWER settings. These bits should be changed, if necessary, by CPU processing.
In writes by the DTC to bits 7 to 4 (DTE) in DMABCR, 1 can be written without first reading 0.
To reactivate a channel set to full address mode, write 1 to both Write Enable A and Write Enable
B for the channel to be reactivated.