dsp56001 Freescale Semiconductor, Inc, dsp56001 Datasheet - Page 50

• Manufacturer Part Number: dsp56001
• Description: Available In An 88 Pin Ceramic Through-hole Package.
• Manufacturer: Freescale Semiconductor, Inc

MOTOROLA
B-50
Figure B-5 shows an alternative clock oscillator circuit used in
the Graphic Equalizer application note (APR2). The 330
tor provides additional current limiting in the crystal. Figure B-6
shows a circuit which waits until Vcc on the DSP is at least 4.5 V
LOGIC
RESET
•
•
2 (2)
Figure B-5. Alternative Clock Circuit from the Graphic Equalizer (APR2)
MC34064
MC33064
1.2 V
•
3 (4)
ref
Figure B-6. Reset Circuit Using MC34064/MC33064
+
-
Notes: 1. IRQA and IRQB must
10 pf
U1
•
•
2. MODA and MODB
•
•
be hardwired.
must be hard wired.
resis-
•
470K
330
20.5
MHz
1 (1)
before initiating a 3.75 ms minimum (150,000T) oscillator stabili-
zation delay required for the on-chip oscillator (only 50T is re-
quired for an external oscillator). This insures that the DSP is op-
erational and stable before releasing the reset signal.
•
t
Where:
t
V
R = 8.2K + 5%
f
DLY
•
•
•
DLY
osc
in
= 5 V
= 20.5 MHz
= RC
= 150,000T min.
10 pf
+5V
DLY
•
•
•
XTAL
EXTAL
In
R
C
1 -
DLY
V
1
V
in
th
- V
V
V
C
T = 25 ns
th
ol
DLY
ol
= 0.4 V
= 2.5 V
RESET
= 1 f + 20%
DSP56001