Error Signals and Flags
10-40
ADSP-2126x SHARC Processor Hardware Reference
SPI DMA Word Count Register (CSPI)
This 16-bit register contains the number of DMA words to be transferred.
When this register decrements from one to zero, the DMA is complete,
and an interrupt may be triggered.
To prematurely end a DMA transfer, software should write the
value one to the Count register so that it will decrement to zero.
Writing a value of zero causes the count to decrement to a negative
number, and this is not advised.
Error Signals and Flags
This section describes the error signals and flags that determine the cause
of transmission errors for an SPI port. The bits
MME
,
TUNF
and
ROVF
are set
in the
SPISTAT
register when a transmission error occurs. Corresponding
bits (
SPIMME
,
SPIUNF
and
SPIOVF
) in the
SPIDMAC
register are set when an
error occurs during a DMA transfer. These sticky bits generate an SPI
interrupt when any one of them are set.
Mode Fault Error (MME)
The
MME
bit is set in the
SPISTAT
register when the
SPIDS
input pin of a
device that is enabled as a master is driven low by some other device in the
system. This occurs in multimaster systems when another device is also
trying to be the master.
To enable this feature, set the
ISSEN
bit in the
SPICTL
register. As soon as
this error is detected, the following actions are taken.
1. The
SPIMS
control bit in
SPICTL
is cleared, configuring the SPI
interface as a slave.
2. The
SPIEN
control bit in
SPICTL
is cleared, disabling the SPI
system.
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 ...