SH7751 Group, SH7751R Group
Section 14 Direct Memory Access Controller (DMAC)
R01UH0457EJ0301 Rev. 3.01
Page 499 of 1128
Sep 24, 2013
•
Channel 6 (SH7751R only): Single or dual address mode. External requests are
accepted.
•
Channel 7 (SH7751R only): Single or dual address mode. External requests are
accepted.
•
In DDT mode, data transfer is carried out by the SH7751 using the
DBREQ
,
BAVL
,
TR
,
TDAC
K, ID [1:0], and D[31:0] signals to perform handshaking between the
external device and the DMAC, and data transfer is carried out by the SH7751R using
the
DBREQ
,
BAVL
,
TR
,
TDACK
, ID [2:0], and D[31:0] signals to perform
handshaking between the external device and the DMAC.
•
Request-queue clear for each channel (SH7751R only)
Request queues can be cleared on a channel-by-channel basis in either of the following
two ways.
⎯
Clearing a request queue by DTR format
The request queues of the relevant channel are cleared when it receives DTR.SZ =
110, DTR.ID = 00, DTR.MD = 11, and DTR.COUNT [7:4]* = [1–8].
⎯
Using software to clear the request queue
The request queues of the relevant channel are cleared by writing a 1 to the
CHCRn.QCL bit (request-queue clear bit) of each channel.
Note: * DTR.COUNT [7:4] (DTR [23:20]): Sets the port as not used. In DDT mode on
the SH7751, an external device and the DMAC perform handshaking using the
DBREQ
,
BAVL
,
TR
,
TDACK
, ID[1:0], and D[31:0] signals during data
transfer. On the SH7751R, the
DBREQ
,
BAVL
,
TR
,
TDACK
, ID[2:0], and
D[31:0] signals are used for handshaking during data transfer between an
external device and the DMAC.