Datasheet

Section 7 DMA Controller (Not Supported in the H8S/2321)
Rev.6.00 Sep. 27, 2007 Page 246 of 1268
REJ09B0220-0600
Bit 9—Data Transfer Acknowledge 0 (DTA0): Enables or disables clearing, when DMA
transfer is performed, of the internal interrupt source selected by the channel 0 data transfer factor
setting.
Bit 9
DTA0 Description
0 Clearing of selected internal interrupt source at time of DMA transfer is disabled
(Initial value)
1 Clearing of selected internal interrupt source at time of DMA transfer is enabled
Bits 10 and 8—Reserved: Can be read or written to. Only 0 should be written to these bits.
Bits 7 and 5—Data Transfer Master Enable (DTME): Together with the DTE bit, these bits
control enabling or disabling of data transfer on the relevant channel. When both the DTME bit
and the DTE bit are set to 1, transfer is enabled for the channel.
If the relevant channel is in the middle of a burst mode transfer when an NMI interrupt is
generated, the DTME bit is cleared, the transfer is interrupted, and bus mastership passes to the
CPU. When the DTME bit is subsequently set to 1 again, the interrupted transfer is resumed. In
block transfer mode, however, the DTME bit is not cleared by an NMI interrupt, and transfer is
not interrupted.
The conditions for the DTME bit being cleared to 0 are as follows:
• When initialization is performed
• When NMI is input in burst mode
• When 0 is written to the DTME bit
The condition for DTME being set to 1 is as follows:
• When 1 is written to DTME after DTME is read as 0
Bit 7—Data Transfer Master Enable 1 (DTME1): Enables or disables data transfer on channel
1.
Bit 7
DTME1 Description
0 Data transfer disabled. In burst mode, cleared to 0 by an NMI interrupt (Initial value)
1 Data transfer enabled