USBee ZX
PWM Controller
This section details the operation of the Pulse Width
Modulator application that comes with the USBee ZX. The Pulse Width Modulator application creates
a Pulse Width Modulated output for all of the 8 digital lines on the USBee
ZX.
Below you see the
application screen.
Each channel outputs a repeating waveform with a 1.46kHz
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 0 shows the PWM value set to 31 (out
of 255) and Signal 1 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).
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Digital Channels Controlled
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8
|
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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
|
1.46kHz
|
|
Control Mechanism
|
Slider Switch
|
|
Channel Output
DriveCurrent
|
4mA
|
|
Output Low Level
|
< 0.8V
|
|
Output High Level
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> 2.4V
|
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