Analog Devices SHARC ADSP-2136 Series Hardware Reference Manual page 247

DMA interrupt errors. Guidelines that programs should follow when per-
forming DMA transfers over the SPI include:
• Do not write to the
DMA operation because DMA data will be overwritten.
• Similarly, do not read from the
DMA receive operations.
• Writes to the
operation are permitted. The
registers are read.
RXSPIx
• Reads from the
transmit DMA.
• Interrupts are generated based on DMA events and are configured
in the
SPIDMACx

To avoid data corruption, enable the SPI port before enabling
DMA.
In order for a transmit DMA operation to begin, the transmit buffer must
initially be empty (
that the
TXSPIx
SPI transfers. For example, the
scratch register for temporary data storage. Writing to the
via the software sets the

For receive DMA in master mode the
FIFO and
Therefore,
junk data in the FIFO and the
cleared before a new DMA is initiated.
ADSP-2136x SHARC Processor Hardware Reference
www.BDTIC.com/ADI
for the ADSP-21362/3/4/5/6 Processors
registers during an active SPI transmit
TXSPIx
registers during an active SPI receive DMA
TXSPIx
registers are allowed at any time during
RXSPIx
registers.
= 0). While this is normally the case, this means
TXS
registers should not be used for any purpose other than
TXSPIx
bit.
TXS
buffer is full (even if the DMA count is zero).
RXSPI
runs for an additional five word transfers filling
SPICLK
Serial Peripheral Interface Ports
registers during active SPI
RXSPIx
register is cleared when the
RXS
registers should not be used as a
stops only when the
SPICLK
buffers. This data must be
RXSPIx
registers
TXSPIx
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