Confidential Draft
3/7/00
CS4281 Programming Manual
100
DS308PRM1
11.5.4
DMA Current Count n (DCCn)
Address:
BA0: 114h, Read-Write, for DMA Engine 0
BA0: 124h, Read-Write, for DMA Engine 1
BA0: 134h, Read-Write, for DMA Engine 2
BA0: 144h, Read-Write, for DMA Engine 3
Default:
00000000h
Definition: Core powered. Holds the current DMA transfer count. The count may be channels or samples
depending on
DMRn.CBC
. If
CBC
is cleared, then this register is decremented once per sample. If
CBC
is set, then the decrement is once per channel. For mono data, 1 sample = 1 channel. For
stereo data, 1 sample = 2 channels (decrement twice if
CBC
set). DCCn will be auto-decremented
on each DMA transaction to always hold the number of transfers to go + 1. When the count
transitions from 00000000 to FFFFFFFFh, TC for this engine is generated. If auto-initialize is set
(
DMRn.AUTO
), then the DMA Base Count register (DBCn), will be loaded into this register and
counting will continue. This register is also written when the DBCn register is written. When the
count reaches (Base Count n) / 2,
HTC
(half
TC
) for this engine is set. Interrupts can be generated
on
TC
and
HTC
. For host access, HDSRn contains the interrupt status, and DCRn contains the
interrupt enables.
Bit Descriptions:
CCU[15:0] Transfer count upper word.
CCH[7:0]
Transfer count high byte.
CCL[7:0]
Transfer count low byte.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
CCU15
CCU14
CCU13
CCU12
CCU11
CCU10
CCU9
CCU8
CCU7
CCU6
CCU5
CCU4
CCU3
CCU2
CCU1
CCU0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CCH7
CCH6
CCH5
CCH4
CCH3
CCH2
CCH1
CCH0
CCL7
CCL6
CCL5
CCL4
CCL3
CCL2
CCL1
CCL0
D
ra
ft
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