ADSP-BF50x Blackfin Processor Hardware Reference
7-43
Direct Memory Access
When the traffic on all DMA channels is taken in the aggregate:
• Transfers between the peripherals and the DMA unit have a maxi-
mum rate of one 16-bit transfer per system clock.
• Transfers between the DMA unit and internal memory (L1) have a
maximum rate of one 16-bit transfer per system clock.
• Transfers between the DMA unit and external memory have a
maximum rate of one 16-bit transfer per system clock.
Some considerations which limit the actual performance include:
• Accesses to internal or external memory which conflict with core
accesses to the same memory. This can cause delays, for example
when both the core and the DMA access the same L1 bank, when
SDRAM pages need to be opened/closed, or when cache lines are
filled.
• Direction changes from
RX
to
TX
on the DAB bus impose a one
SCLK
cycle delay.
• Direction changes on the DCB bus (for example, write followed by
read) to the same bank of internal memory can impose delays.
• Direction changes (for example, read followed by write) on the
DEB bus to external memory can each impose a several-cycle delay.
• MMR accesses to DMA registers other than
DMAx_CONFIG
,
DMAx_IRQ_STATUS
, or
DMAx_PERIPHERAL_MAP
stall all DMA activity
for one cycle per 16-bit word transferred. In contrast, MMR
accesses to the control/status registers do not cause stalls or wait
states.
• Reads from DMA registers other than control/status registers use
one PAB bus wait state, delaying the core for several core clocks.
Содержание EZ-KIT Lite ADSP-BF506F
Страница 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 132: ...Unique Information for the ADSP BF50x Processor 4 22 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 342: ...Unique Information for the ADSP BF50x Processor 7 106 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 484: ...Unique Information for the ADSP BF50x Processor 10 60 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 493: ...ADSP BF50x Blackfin Processor Hardware Reference 11 9 Core Timer Unique Information for the ADSP BF50x Processor None ...
Страница 494: ...Unique Information for the ADSP BF50x Processor 11 10 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 506: ...Unique Information for the ADSP BF50x Processor 12 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 544: ...Unique Information for the ADSP BF50x Processor 13 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 712: ...Unique Information for the ADSP BF50x Processor 16 62 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 972: ...Unique Information for the ADSP BF50x Processor 20 38 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Страница 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...