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DMA Registers
5-102
ADSP-BF537 Blackfin Processor Hardware Reference
A block done interrupt is generated when
BCOUNT
decrements to 0. If the
MBDI
bit in the
HMDMAx_CONTROL
register is set, the interrupt is suppressed
until
ECOUNT
is 0. Note if
BCINIT
is 0, no block done interrupt is gener-
ated, since no DMA requests were generated or grants received.
HMDMAx_ECOUNT Registers
The handshake MDMA current edge count register (
HMDMAx_ECOUNT)
,
, holds a signed number of edges remaining to be
serviced. This number is in a signed two’s complement representation. An
edge is detected on the respective
DMARx
input. Requests occur if this count
is greater than or equal to 0, and
BCOUNT
is greater than 0.
When the handshake mode is enabled,
ECOUNT
is loaded and the resulting
number of requests is:
Number of edges + N
,
where
N
is the number loaded from
ECINIT
. The number
N
is a positively
or negatively signed number. Examples:
• 7FFF = 32767 edges remaining
• 0000 = 0 edges remaining
• 8000 = –32768: ignore the next 32768 edges
Figure 5-21. Handshake MDMA Current Block Count Registers
0
0
0
0
0
0
15 14
13 12
11 10
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
0
Handshake MDMA Current Block Count Register (HMDMAx_BCOUNT)
BCOUNT[15:0] (Transfers
Remaining for Current Edge)
Reset = 0x0000
HMDMA0:
0xFFC0 3318
HMDMA1:
0xFFC0 3358
Содержание Blackfin ADSP-BF537
Страница 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
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Страница 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...