| 摘要 |
A microcontroller based analog-to-digital converter is disclosed. The microcontroller is coupled to an output of a comparator. The comparator includes an input for receiving an unknown analog voltage and an input coupled to a capacitor. The capacitor is also coupled to the microcontroller through a resistor. Based upon the output of the comparator, the microcontroller provides a pulsed input signal with a predetermined duty cycle to the capacitor. The duty cycles for "high" pulses and "low" pulses are individually set to match a selected input voltage range. The rate at which pulses are applied to the capacitor is adjusted until the voltage on the capacitor matches the input voltage being measured. The pulsed input signal is monitored to establish a pulse count. Based upon the pulse count, the unknown analog voltage value is converted to a corresponding digital voltage value.
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