30 lines
822 B
JavaScript
30 lines
822 B
JavaScript
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Utils = {
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// Returns { period: int, duty: int }
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// Calculated based on params value, freq, pulseWidth = { min: int, max: int }
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// pulseWidth min and max need to be specified in microseconds
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periodAndDuty = function(scaledValue, freq, pulseWidth, polarity) {
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var period, duty, maxDuty;
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polarity = polarity || 'high';
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period = Math.round(1.0e9 / freq);
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if (pulseWidth != null) {
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var pulseWidthMin = pulseWidth.min * 1000,
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pulseWidthMax = puhlseWidth.max * 1000;
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maxDuty = pulseWidthMax - pulseWidthMin;
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duty = Math.round(pulseWidthMin + (maxDuty * scaledDuty));
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} else {
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duty = Math.round(period * scaledDuty);
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}
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if (polarity == 'low') {
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duty = period - duty;
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}
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return { period: period, duty: duty };
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};
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};
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module.exports = Utils;
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