SPORT Registers
11-32
ADSP-BF535 Blackfin Processor Hardware Reference
Configuration register. The DMA Configuration register maintains
real-time DMA buffer status.
Figure 11-17
represents the
SPORTx_CONFIG_DMA_RX
registers.
Each SPORT DMA channel has a DMA Enable bit (
DEN
) for each of the
serial ports. When DMA is not enabled for a particular channel, the
SPORT generates an interrupt every time it receives a data word.
When the Interrupt on Completion bit of the
SPORTx_CONFIG_DMA_RX
reg-
ister is set, bit 0 of the
SPORTx_IRQSTAT_RX
register is set and a DMA
interrupt is generated after the final transfer of data. Final transfer of data
occurs when DMA count = 0, as specified by the descriptor work block.
DMA transfer size can be set to 8, 16, or 32 bits. This provides flexibility
in how data is packed in memory. For DMA writes to memory in excess of
the 16-bit FIFO size, the upper bits are padded with 0s. For DMA writes
to memory smaller than the 16-bit FIFO size, only the LSBs of the FIFO
are written. A DMA read of memory greater than the 16-bit FIFO size
reads only the LSBs of memory into the FIFO. For DMA reads of memory
smaller than the FIFO size, the least significant bits of the FIFO are
loaded and the remaining FIFO bits have unknown values. DMA data
transfer size is determined by setting the Data Size Bit 0 and Data Size Bit
1 bits in the
SPORTx_CONFIG_DMA_RX
register.
When the Interrupt on Error bit is set, a receive overflow error results in
bit 1 of the
SPORTx_IRQSTAT_RX
register being set and a DMA interrupt
being generated.
The Receive Overflow Error bit is set if an overflow condition occurs.
This bit is sticky only during the current work block. It is cleared on the
next descriptor fetch.
The DMA Completion Status bit reflects the current error condition. It is
set if a receive overflow error occurs. When the current descriptor work
block completes (DMA count = 0), the value of this bit is written to
memory as a record of the completion result, and the bit is cleared for the
next data transfer.
Содержание ADSP-BF535 Blackfin
Страница 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 312: ...Working With Memory 6 86 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 332: ...System Interfaces 7 20 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 360: ...Dynamic Power Management Controller 8 28 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 446: ...Beginning and Ending an SPI Transfer 10 40 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 522: ...Timing Examples 11 76 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 562: ...IrDA Support 12 40 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 608: ...PCI I O Issues 13 46 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 672: ...References 14 64 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 810: ...SDRAM Controller SDC 18 86 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 811: ...ADSP BF535 Blackfin Processor Hardware Reference 18 87 External Bus Interface Unit...
Страница 812: ...SDRAM Controller SDC 18 88 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 860: ...DMA Bus Debug Registers 20 30 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 908: ...SDRAM Controller External Bus Interface Unit B 36 ADSP BF535 Blackfin Processor Hardware Reference...