HD64F2357VF13 Datasheet, PDF (263/1049 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

7.5.15 NMI Interrupts and DMAC
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 the DTME bit are 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 7-36 shows the
procedure for continuing transfer when it has been interrupted by an NMI interrupt on a channel designated for burst mode
transfer.
Resumption of
transfer on interrupted
channel
DTE = 1
[1]
DTME = 0
No
Yes
Set DTME bit to 1
[2]
[1] Check that DTE = 1 and
DTME = 0 in DMABCRL
[2] Write 1 to the DTME bit.
Transfer continues
Transfer ends
Figure 7-36 Example of Procedure for Continuing Transfer on Channel Interrupted by NMI Interrupt
Rev.6.00 Oct.28.2004 page 233 of 1016
REJ09B0138-0600H