COP881C Datasheet, PDF (12/30 Pages) National Semiconductor (TI) – Microcontrollers

Functional Description (Continued)
Table II shows the variation in the oscillator frequencies as
functions of the component (R and C) values
TL DD 10802–6
RC t 5X Power Supply Rise Time
FIGURE 4 Recommended Reset Circuit
OSCILLATOR CIRCUITS
Figure 5 shows the three clock oscillator configurations
A CRYSTAL OSCILLATOR
The device can be driven by a crystal clock The crystal
network is connected between the pins CKI and CKO
Table I shows the component values required for various
standard crystal values
B EXTERNAL OSCILLATOR
CKI can be driven by an external clock signal CKO is avail-
able as a general purpose input and or HALT restart con-
trol
C R C OSCILLATOR
CKI is configured as a single pin RC controlled Schmitt trig-
ger oscillator CKO is available as a general purpose input
and or HALT restart control
TL DD 10802 – 7
FIGURE 5 Crystal and R-C Connection Diagrams
OSCILLATOR MASK OPTIONS
The device can be driven by clock inputs between DC and
10 MHz
R1
(kX)
0
0
56
R2
(MX)
1
1
1
TABLE I Crystal Oscillator Configuration T_A e 25 C
C1
C2
CKI Freq
(pF)
(pF)
(MHz)
30
30 – 36
30
30 – 36
200
100 – 150
10
4
0 455
Conditions
V_CC e 5V
V_CC e 2 5V
V_CC e 5V
TABLE II RC Oscillator Configuration T_A e 25 C
R
C
CKI Freq
(kX)
(pF)
(MHz)
Instr Cycle
(ms)
33
82
2 2 to 2 7
3 7 to 4 6
56
100
1 1 to 1 3
7 4 to 9 0
68
100
0 9 to 1 1
8 8 to 10 8
Note (R C Oscillator Configuration) 3k s R s 200k 50 pF s C s 200 pF
Conditions
V_CC e 5V
V_CC e 5V
V_CC e 5V
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