cop8sec520m National Semiconductor Corporation, cop8sec520m Datasheet - Page 14

• Manufacturer Part Number: cop8sec520m
• Description: 8-bit Cmos Based Microcontrollers With Memory Bytes Eeram
• Manufacturer: National Semiconductor Corporation

www.national.com
5.0 Functional Description
5.9.1 Crystal Oscillator
CKI and CKO can be connected to make a closed loop crys-
tal (or resonator) controlled oscillator.
Table 1 shows the component values required for various
standard crystal values.
R1 (k )
5.6
0
0
TABLE 1. Crystal Oscillator Configuration,
R2 (M )
1
1
1
T
A
= 25˚C, V
C1 (pF)
100
32
39
DS100973-50
CC
= 5V
100–156
C2 (pF)
32
39
FIGURE 10. Crystal and R/C Oscillator
(Continued)
CKI Freq.
(MHz)
0.455
10
4
14
5.9.2 R/C Oscillator
By selecting CKI as a single pin oscillator input, a single pin
R/C oscillator circuit can be connected to it. CKO is available
as a general purpose input, and /or HALT restart input.
Table 2 shows the variation in the oscillator frequency as a
function of the component (R and C) value.
R (k )
3.3
5.6
6.8
TABLE 2. R/C Oscillator Configuration,
C (pF)
100
100
82
T
A
= 25˚C, V
CKI Freq.(MHz)
2.2 to 2.7
1.1 to 1.3
0.9 to 1.1
DS100973-51
CC
= 5V
Instr. Cycle (µs)
8.8 to 10.8
3.7 to 4.6
7.4 to 9.0