Setting Up DMA Parameter Registers
7-28
ADSP-2126x SHARC Processor Hardware Reference
If the I/O processor modifies the index register past the maximum
19-bit value to indicate an address out of internal memory, the
index wraps around to zero. With the offset for the ADSP-2126x
processor, the wraparound address is 0x0008 0000.
If a program loads the count register with zero, the I/O processor
does not disable DMA transfers on that channel. The I/O proces-
sor interprets the zero as a request for 2
16
transfers. This count
occurs because the I/O processor starts the first transfer before test-
ing the count value. The only way to disable a DMA channel is to
clear its DMA enable bit.
If a DMA channel is disabled, the I/O processor does not service
requests for that channel, whether or not the channel has data to
transfer.
The processor’s 22 DMA channels are numbered as shown in
This table also shows the control, parameter, and data buffer registers that
correspond to each channel.
In SP01, SP1 has a higher priority. Similarly, for SP23 and SP45,
the odd numbered SPs have a higher priority (SP3, SP5).
Table 7-5. DMA Channel Registers: Controls, Parameters
and Buffers
DMA
Channel
Number
Control
Registers
Parameter Registers
Buffer Registers
Description
0
SPCTL1
IISP1A, IMSP1A,
CSP1A, CPSP1A
RXSP1A, TXSP1A
Serial Port 1A Data
1
SPCTL1
IISP1B, IMSP1B,
CSP1B, CPSP1B
RXSP1B, TXSP1B
Serial Port 1B Data
2
SPCTL0
IISP0A, IMSP0A,
CSP0A, CPSP0A
RXSP0A, TXSP0A
Serial Port 0A Data
3
SPCTL0
IISP0B, IMSP0B,
CSP0B, CPSP0B
RXSP0B, TXSP0B
Serial Port 0B Data
Содержание ADSP-21261 SHARC
Страница 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Страница 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Страница 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Страница 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Страница 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Страница 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...