Analog Devices ADSP-BF59x Blackfin, Hardware Reference Manual, Page: 505 / 772

ADSP-BF59x Blackfin Processor Hardware Reference 13-51
SPI-Compatible Port Controller
Listing 13-8. Stopping a Transfer
SPI_DMA_INTERRUPT_HANDLER:
P0.L = lo(DMA7_IRQ_STATUS);
P0.H = hi(DMA7_IRQ_STATUS);
R0 = 1 ;
W[P0] = R0 ; /* Clear DMA interrupt */
/* Wait for DMA to complete */
P0.L = lo(DMA7_IRQ_STATUS);
P0.H = hi(DMA7_IRQ_STATUS);
R0 = DMA_RUN; /* 0x08 */
CHECK_DMA_COMPLETE: /* Poll for DMA_RUN bit to clear */
R3 = W[P0] (Z);
R1 = R3 & R0;
CC = R1 == 0;
IF !CC JUMP CHECK_DMA_COMPLETE;
/* Wait for TXS to clear */
P0.L = lo(SPI_STAT);
P0.H = hi(SPI_STAT);
R1 = TXS; /* 0x08 */
Check_TXS: /* Poll for TXS = 0 */
R2 = W[P0] (Z);
R2 = R2 & R1;
CC = R0 == 0;
IF !CC JUMP Check_TXS;
R2 = W[P0] (Z); /* Check if TXS stays clear for 2 reads */
R2 = R2 & R1;
CC = R0 == 0;
IF !CC JUMP Check_TXS;