ADSP-2126x SHARC Processor Hardware Reference
10-33
Serial Peripheral Interface Port
During IOP-driven transfers (DMA), an SPI interrupt is triggered in these
instances:
1. When a single DMA transfer completes
2. When a number of DMA sequences (if DMA chaining is enabled)
completes
3. When a DMA error has occurred
Again, the
TIMOD
register must be initialized properly to enable DMA
interrupts.
All of these interrupts are serviced using the high priority (
SPIHI
) or low
priority (
SPILI
) SPI interrupt. Whenever an SPI interrupt occurs (regard-
less of the cause), both
SPILI
and
SPIHI
are latched. Programs specify the
SPI interrupt priority by masking (disabling) one of the interrupts. To ser-
vice the SPI port using the high priority interrupt, unmask (set = 1) the
SPIHI
bit (bit 12) in the
IMASK
register. To service the SPI port using the
low priority interrupt, unmask (set = 1) the
SPILIMSK
bit (bit 19) in the
LIRPTL
register. For a list of these bits, see
To globally enable interrupts set (= 1), the
IRPTEN
bit in the
MODE1
register.
When using DMA transfers, programs must also specify whether to gener-
ate interrupts based on transfer or error status. For DMA transfer status
based interrupts, set the
INTEN
bit in the
SPIDMAC
register; otherwise, set
the
INTERR
bit to trigger the interrupt if one of the error conditions is trig-
gered during the transmission—multimaster error (MME), transmit
buffer underflow (
TUNF
– only if
SPIRCV
= 0), or receive buffer overflow
(
ROVF
– only if
SPIRCV
= 1). During core-driven transfers, the
TUNF
and
ROVF
error conditions do not generate interrupts.
When DMA is disabled, the processor core may read from the
RXSPI
regis-
ter or write to the
TXSPI
data buffer. The
RXSPI
and
TXSPI
buffers are
memory-mapped IOP registers. A maskable interrupt is generated when
the receive buffer is not empty or the transmit buffer is not full. The
TUNF
and
ROVF
error conditions do not generate interrupts in these modes.
Summary of Contents for ADSP-21261 SHARC
Page 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Page 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Page 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Page 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Page 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Page 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Page 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Page 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Page 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Page 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Page 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Page 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...