ADSP-BF59x Blackfin Processor Hardware Reference
17-3
System Design
Bus Priorities
For an explanation of prioritization between the various internal buses,
refer to
“Chip Bus Hierarchy” on page 3-1
.
High-Frequency Design Considerations
Because the processor can operate at very fast clock frequencies, signal
integrity and noise problems must be considered for circuit board design
and layout. The following sections discuss these topics and suggest various
techniques to use when designing and debugging signal processing
systems.
Signal Integrity
In addition to reducing signal length and capacitive loading, critical sig-
nals should be treated like transmission lines.
Capacitive loading and signal length of buses can be reduced by using a
buffer for devices that operate with wait states. This reduces the capaci-
tance on signals tied to the zero-wait-state devices, allowing these signals
to switch faster and reducing noise-producing current spikes.
Use simple signal integrity methods to prevent transmission line reflec-
tions that may cause extraneous extra clock and sync signals. Additionally,
avoid overshoot and undershoot that can cause long term damage to input
pins.
Some signals are especially critical for short trace length and usually
require series termination. The
CLKIN
pin should have impedance match-
ing series resistance at its driver. SPORT interface signals
TCLK
,
RCLK
,
RFS
,
and
TFS
should use some termination. Although the serial ports may be
operated at a slow rate, the output drivers still have fast edge rates and for
longer distances the drivers often require resistive termination located at
Summary of Contents for ADSP-BF59x Blackfin
Page 64: ...Development Tools 1 22 ADSP BF59x Blackfin Processor Hardware Reference...
Page 74: ...Processor Specific MMRs 2 10 ADSP BF59x Blackfin Processor Hardware Reference...
Page 244: ...Programming Examples 6 40 ADSP BF59x Blackfin Processor Hardware Reference...
Page 700: ...Programming Examples 16 78 ADSP BF59x Blackfin Processor Hardware Reference...
Page 738: ...Boundary Scan Architecture B 8 ADSP BF59x Blackfin Processor Hardware Reference...
