MC68HC05SU3A Datasheet, PDF (22/80 Pages) Freescale Semiconductor, Inc – Fully static chip design featuring the industry standard 8-bit M68HC05 core

Freescale Semiconductor, Inc.
2.2.3 RC Oscillator Option
2
This configuration is intended to be the lowest cost option in applications where oscillator accuracy
is not important. An internal constant current source and a capacitor have been integrated on-chip,
connected between the OSC2 pin and VSS. Thus by either connecting a resistor to VDD from
OSC2 or by putting a wire strap between OSC1 and OSC2 self-oscillations at the frequency as
shown in Figure 2-2 and Figure 2-3 can be induced.
3.5
3.0
2.5
2.0
1.5
1.0
50 70 90 110 130 150 170 190 210 230
Resistance (KΩ)
Figure 2-2 Typical Oscillator Frequency for Selected External Resistor
2.25
T = 0 °C
2.00
T = 25 °C
1.75
T = 50 °C
1.50
1.25
1.00
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
VDD (V)
Figure 2-3 Typical Oscillator Frequency for Wire-Strap Connection
TPG
PIN DESCRIPTIONS
MC68HC05SU3A
2-4
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