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This section details the operation of the Pulse Width Modulator application that comes with the USBee DX. The Pulse Width Modulator application creates a Pulse Width Modulated output for all of the 16 digital lines on the USBee DX.
Click OK to enter the application. Below you see the application screen.
Each channel outputs a repeating waveform with a 1kHz frequency. The period of the repeating waveform is made up of a high duration followed by a low duration and has 256 steps. The length of the High duration is the PWM value that is shown. The length of the Low duration is 256 – the High duration.
You can create a simple analog output voltage by using a series resistor and a capacitor to ground on each channel.
The above shows 2 outputs of the PWM Controller. Signal 1 shows the PWM value set to 31 (out of 255) and Signal 0 shows the PWM value of 137. A value of 0 is all low, and a value of 255 is mostly high (one out of 256 is low).
PWM Controller Specifications
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Digital Channels Controlled
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16
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Analog Channels Controlled
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0
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Resolution
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256 steps
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PWM Frequency
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1.02kHz
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Control Mechanism
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Slider Switch
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Channel Output Drive Current
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4mA
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Output Low Level
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< 0.8V
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Output High Level
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> 2.4V
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