HT46R068B/HT46R069B
Enhanced A/D Type 8-bit OTP MCU
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Crystal/Resonator Oscillator — HXT
Crystal Oscillator C1 and C2 Values
Crystal Frequency
1ꢃMHz
C1
8pF
8pF
8pF
100pF
C2
10pF
10pF
10pF
100pF
8MHz
4MHz
1MHz
Note: C1 and Cꢃ valꢀes aꢁe foꢁ gꢀidance onlꢂ.
Crystal Recommended Capacitor Values
External RC Oscillator – ERC
Using the ERC oscillator only requires that a resistor, with a value between 24kΩ and 1.5MΩ,
is connected between OSC1 and VDD, and a capacitor is connected between OSC and ground,
providing a low cost oscillator configuration. It is only the external resistor that determines the
oscillation frequency; the external capacitor has no influence over the frequency and is connected
for stability purposes only. Device trimming during the manufacturing process and the inclusion of
internal frequency compensation circuits are used to ensure that the influence of the power supply
voltage, temperature and process variations on the oscillation frequency are minimised. As a
resistance/frequency reference point, it can be noted that with an external 120K resistor connected
and with a 5V voltage power supply and temperature of 25 degrees, the oscillator will have a
frequency of 4MHz within a tolerance of 2%. Here only the OSC1 pin is used, which is shared
with I/O pin PA6, leaving pin PA5 free for use as a normal I/O pin.
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External RC Oscillator — ERC
Rev. 1.00
ꢃ9
�anꢀaꢁꢂ ꢃꢄꢅ ꢃ011
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
