COPCH823CJ Datasheet, PDF (9/32 Pages) National Semiconductor (TI) – 8-bit Microcontroller with with Multi-Input Wake Up and Brown Detecter

Functional Description (Continued)
Oscillator Circuits
EXTERNAL OSCILLATOR
CKI can be driven by an external clock signal provided it
meets the specified duty cycle rise and fall times and input
levels CKO is available as a general purpose input G7
and or Halt control
CRYSTAL OSCILLATOR
By selecting CKO as a clock output CKI and CKO can be
connected to create a crystal controlled oscillator Table I
shows the component values required for various standard
crystal values
R C OSCILLATOR
By selecting CKI as a single pin oscillator CKI can make a
R C oscillator CKO is available as a general purpose input
and or HALT control Table II shows variation in the oscilla-
tor frequencies as functions of the component (R and C)
values
R1
(kX)
0
0
56
TL DD 11208 – 7
FIGURE 5 Clock Oscillator Configurations
TABLE I Crystal Oscillator Configuration
R2
C1
C2
CKI Freq
(MX)
(pF)
(pF)
(MHz)
1
30
30 – 36
10
1
30
30 – 36
4
1
100
100 – 156
0 455
Conditions
V_CC e 5V
V_CC e 5V
V_CC e 5V
R
(kX)
33
56
68
TABLE II RC Oscillator Configuration (Part-To-Part Variation)
C
CK1 Freq
(pF)
(MHz)
Instr Cycle
(ms)
Conditions
82
2 2 to 2 7
100
1 1 to 1 3
100
0 9 to 1 1
3 7 to 4 6
7 4 to 9 0
8 8 to 10 8
V_CC e 5V
V_CC e 5V
V_CC e 5V
9
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