High-Frequency Design Considerations
25-8
ADSP-BF50x Blackfin Processor Hardware Reference
Note that the instantaneous voltage on both internal and external power
pins must at all times be within the recommended operating conditions as
specified in the product data sheet. Local “bulk capacitance” (many micro-
farads) is also necessary. Although all capacitors should be kept close to
the power consuming device, small capacitance values should be the clos-
est and larger values may be placed further from the chip.
5 Volt Tolerance
Outputs that connect to inputs on 5 V devices can float or be pulled up to
5 V. Most Blackfin pins are not 5 V tolerant. There are a few exceptions
such as the TWI pins. Level shifters are required on all other Blackfin pins
to keep the pin voltage at or below absolute maximum ratings.
Test Point Access
The debug process is aided by test points on signals such as
CLKOUT
or
SCLK
, bank selects,
PPICLK
, and
RESET
. If selection pins such as boot mode
are connected directly to power or ground, they are inaccessible under a
BGA chip. Use pull-up and pull-down resistors instead.
Oscilloscope Probes
When making high-speed measurements, be sure to use a “bayonet” type
or similarly short (< 0.5 inch) ground clip, attached to the tip of the oscil-
loscope probe. The probe should be a low-capacitance active probe
with 3 pF or less of loading. The use of a standard ground clip with
4 inches of ground lead causes ringing to be seen on the displayed trace
and makes the signal appear to have excessive overshoot and undershoot.
To see the signals accurately, a 1 GHz or better sampling oscilloscope is
needed.
Summary of Contents for EZ-KIT Lite ADSP-BF506F
Page 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Page 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...