System Interfaces
7-8
ADSP-BF535 Blackfin Processor Hardware Reference
The system interfaces operate at a divided frequency from that of the core.
Peripheral Bus (PAB)
The ADSP-BF535 processor has a dedicated peripheral bus. A low latency
peripheral bus keeps core stalls to a minimum and allows for manageable
interrupt latencies to time-critical peripherals. All peripheral resources
accessed through the PAB are mapped into the System MMR space of the
ADSP-BF535 processor memory map. Both the core and the PCI Con-
troller can access system MMR space through the PAB bus.
Both the core processor and the PCI masters have byte addressability, but
the programming model is restricted to only 16- or 32-bit (aligned) access
to the system MMRs. Byte access to this region is not supported.
PAB Arbitration
The core, through the Core D0 bus, and the PCI port, through the EMB,
are the only masters on this bus. A fixed priority arbitration policy is sup-
ported. The PCI port interface unit has highest priority. Maximum
arbitration latency for either master is 2
SCLK
cycles.
PAB Performance
For PAB, the primary performance criteria is latency. Transfer latencies
for both read and write transfers on the PAB are 2
SCLK
cycles.
The core or the PCI controller can transfer up to 32 bits per access to the
PAB slaves. Configured with a 1:2 core clock ratio, the first and subse-
quent system MMR (single cycle) read or write accesses take 4 core clocks
(
CCLK
) of latency. Configured with a 1:2.5 or 1:3 core clock ratio, the first
and subsequent system MMR (single cycle) read or write accesses take 6
core clocks (
CCLK
) of latency.
With a 300 MHz core clock and a 1:2.5 bus clock ratio, the peak periph-
eral bus throughput is 240 MBytes per second.
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...