Datasheet

Table Of Contents
Section 7 DMA Controller (DMAC)
REJ09B0140-0900 Rev. 9.00 Page 187 of 846
Sep 16, 2010
H8S/2215 Group
ETCRB is decremented by 1 every block transfer, and when the count reaches H'0000 the DTE bit
is cleared and transfer ends. If the DTIE bit is set to 1 at this point, an interrupt request is sent to
the CPU or DTC. Figure 7.13 shows the operation flow in block transfer mode.
Acquire bus
ETCRAL = ETCRAL–1
Transfer request?
ETCRAL = H'00
Release bus
BLKDIR = 0
ETCRAL = ETCRAH
ETCRB = ETCRB – 1
ETCRB = H'0000
Start
(DTE = DTME = 1)
Read address specified by MARA
MARA = MARA + SAIDE · (–1)
SAID ·
2
DTSZ
Write to address specified by MARB
MARB = MARB + DAIDE · (–1)
DAID
· 2
DTSZ
MARB = MARB – DAIDE
·
(–1)
DAID
·
2
DTSZ
·
ETCRAH
MARA = MARA – SAIDE
·
(–1)
SAID
·
2
DTSZ
·
ETCRAH
No
Yes
No
Yes
No
Yes
No
Yes
Clear DTE bit to 0
to end transfer
Figure 7.13 Operation Flow in Block Transfer Mode