COP8SA-DM National Semiconductor, COP8SA-DM Datasheet - Page 28

• Manufacturer Part Number: COP8SA-DM
• Description: MODULE DEBUGGING FOR COP8SA
• Manufacturer: National Semiconductor

Specifications of COP8SA-DM

• Module/board Type: Debugger Module
• For Use With/related Products: Cop 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *COP8SA-DM

External Clock Circuitry
Divider
Clock Generator
Instruction Cycle Frequency
Figure 1-7 Clock Generation
1.7.5
Oscillator Circuits
Typically there are three types of clock oscillator options available: external oscillator,
R/C oscillator, or crystal oscillator.
External Oscillator
An external square wave clock source is generated outside and presented to the
microcontroller clock input pin. The clock source must meet the specified duty cycle, rise
and fall times, and input level.
Clock Input
Figure 1-8 External Oscillator
R/C Oscillator
The R/C (resistor/capacitor) oscillator requires the use of external R/C components or R/C
integrated on-chip. The oscillator frequency is a function of the resistance and
capacitance values.
V
CC
Clock Input
R
or Clock input pin open for internal R/C
C
Figure 1-9 R/C Oscillator
Crystal Oscillator
The phase shift oscillator referred to as the Pierce Oscillator has many desirable
characteristics. It provides a large output signal and drives the crystal at a low power
level. The low power level leads to low power dissipation, especially at higher frequencies.
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MICROCONTROLLER BASICS