r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 412

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

Section 7 DMA Controller (DMAC)
7.5.14
When an NMI interrupt is requested, burst mode transfer in full address mode is interrupted. An
NMI interrupt does not affect the operation of the DMAC in other modes.
In full address mode, transfer is enabled for a channel when both the DTE bit and DTME bit in
DMABCRLare set to 1. With burst mode setting, the DTME bit is cleared when an NMI interrupt
is requested.
If the DTME bit is cleared during burst mode transfer, the DMAC discontinues transfer on
completion of the 1-byte or 1-word transfer in progress, then releases the bus, which passes to the
CPU.
The channel on which transfer was interrupted can be restarted by setting the DTME bit to 1
again. Figure 7.35 shows the procedure for continuing transfer when it has been interrupted by an
NMI interrupt on a channel designated for burst mode transfer.
Rev. 1.00 Sep. 19, 2008 Page 384 of 1270
REJ09B0466-0100
Figure 7.35 Example of Procedure for Continuing Transfer on Channel Interrupted by
transfer on interrupted
DMAC and NMI Interrupts
Transfer continues
Set DTME bit to 1
Resumption of
DTME bit = 0
DTE bit = 1
channel
Yes
No
[1]
[2]
NMI Interrupt
Transfer ends
[1]
[2]
Check that DTE = 1 and
DTME = 0 in DMABCRL.
Write 1 to the DTME bit.