ADSP-BF537 Blackfin Processor Hardware Reference
5-43
Direct Memory Access
half the FIFO depth. Then, the MDMA does not start consuming data as
long as the FIFO is not half filled.
On internal system buses, memory DMA channels have lower priority
than other DMAs. In busy systems it might happen that the memory
DMAs tend to starve. As this is not acceptable when transferring data
through high-speed FIFOs, the handshake mode provides a high-water
functionality to increase the MDMA’s priority. With the
UTE
bit in the
HMDMAx_CONTROL
register set, the MDMA gets higher priority as soon as a
(positive) value in the
HMDMAx_ECOUNT
register becomes higher than the
threshold held by the
HMDMAx_ECURGENT
register.
HMDMA Interrupts
In addition to the normal MDMA interrupt channels, the handshake
hardware provides two new interrupt sources for each
DMARx
input. All
interrupt sources are routed to the global DMA error interrupt channel.
The
HMDMAx_CONTROL
registers provide interrupt enable and status bits.
The interrupt status bits require a write-1-to-clear operation to cancel the
interrupt request.
Figure 5-5. Receive DMA Example Connection
RD
AMSx
1024K x 16 FIFO
BLACKFIN
EF
D0 .. D15
DMARx
WR
O0 .. O15
I0 .. I15
ARE
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...