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Section 7 DMA Controller
• Block transfer mode
ETCRA
Bit
7
Initial value
Read/Write
R/W
Bit
7
Initial value
Read/Write
R/W
ETCRB
Bit
15
Initial value
Read/Write
R/W
In block transfer mode, ETCRAH functions as an 8-bit block size counter. ETCRAL holds the
initial block size. ETCRAH is decremented by 1 each time one byte or word is transferred. When
the count reaches H'00, ETCRAH is reloaded from ETCRAL. Blocks consisting of an arbitrary
number of bytes or words can be transferred repeatedly by setting the same initial block size value
in ETCRAH and ETCRAL.
In block transfer mode ETCRB functions as a 16-bit block transfer counter. ETCRB is
decremented by 1 each time one block is transferred. The transfer ends when the count reaches
H'0000.
The ETCRs are not initialized by a reset or in standby mode.
Rev. 4.00 Jan 26, 2006 page 222 of 938
REJ09B0276-0400
6
5
R/W
R/W
6
5
R/W
R/W
14
13
12
11
10
R/W
R/W
R/W
R/W
R/W
4
3
Undetermined
R/W
R/W
ETCRAH
Block size counter
4
3
Undetermined
R/W
R/W
ETCRAL
Initial block size
9
8
7
6
Undetermined
R/W
R/W
R/W
R/W
R/W
Block transfer counter
2
1
R/W
R/W
R/W
2
1
R/W
R/W
R/W
5
4
3
2
1
R/W
R/W
R/W
R/W
0
0
0
R/W
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