179
7.2.3
DTC Source Address Register (SAR)
23
22
21
20
19
4
3
2
1
0
Bit
Initial value
:
:
—
Unde-
fined
R/W
:
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
SAR is a 24-bit register that designates the source address of data to be transferred by the DTC.
For word-size transfer, specify an even source address.
7.2.4
DTC Destination Address Register (DAR)
23
22
21
20
19
4
3
2
1
0
Bit
Initial value
:
:
—
Unde-
fined
R/W
:
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
DAR is a 24-bit register that designates the destination address of data to be transferred by the
DTC. For word-size transfer, specify an even destination address.
7.2.5
DTC Transfer Count Register A (CRA)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CRAH
CRAL
Bit
Initial value
:
:
—
Unde-
fined
R/W
:
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
—
Unde-
fined
CRA is a 16-bit register that designates the number of times data is to be transferred by the DTC.
In normal mode, the entire CRA functions as a 16-bit transfer counter (1 to 65536). It is
decremented by 1 every time data is transferred, and transfer ends when the count reaches H'0000.
In repeat mode or block transfer mode, the CRA is divided into two parts: the upper 8 bits
(CRAH) and the lower 8 bits (CRAL). CRAH holds the number of transfers while CRAL
functions as an 8-bit transfer counter (1 to 256). CRAL is decremented by 1 every time data is
transferred, and the contents of CRAH are sent when the count reaches H'00. This operation is
repeated.