Difference between revisions of "PIC32MX: PWM Motor Control"
Andrew Long (talk | contribs) (New page: Pulse Width Modulation, or PWM, is a technique used to vary the ''average'' magnitude of a signal by changing its '''duty cycle''' (the proportion of time that a signal is active or "high"...) |
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Pulse Width Modulation, or PWM, is a technique used to vary the ''average'' magnitude of a signal by changing its '''duty cycle''' (the proportion of time that a signal is active or "high"). For a more in-depth introduction to PWM motor control click [[Pulse Width Modulation|here]]. |
Pulse Width Modulation, or PWM, is a technique used to vary the ''average'' magnitude of a signal by changing its '''duty cycle''' (the proportion of time that a signal is active or "high"). For a more in-depth introduction to PWM motor control click [[Pulse Width Modulation|here]]. |
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PWM for PIC32 is discussed in more detail in the [http://ww1.microchip.com/downloads/en/DeviceDoc/61111D.pdf Output Compare documention]. |
PWM for PIC32 is discussed in more detail in the [http://ww1.microchip.com/downloads/en/DeviceDoc/61111D.pdf Microchip Output Compare documention]. |
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==Available Pins== |
==Available Pins== |
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The |
The pins available for PWM are 5 input pins (OC1, OC2, OC3, OC4, and OC5) and 2 output pins (OCFA and OCFB). The output pins are for fault pin protection. |
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==General Approach== |
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PWM can be set up by either changing the directly altering register bits or using the functions in outcompare.h (a header file included in the peripheral library (plib.h). The latter case is more straightforward and easier. This wiki describes how to use the outcompare functions. The register bits approach is described in detail in the[http://ww1.microchip.com/downloads/en/DeviceDoc/61111D.pdf Microchip Output Compare documention]. |
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There are three main functions that are used for PWM. |
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void OpenOCX( config, value1, value2) |
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where X is the module that you want to use (1-5). This function configures the OCX module and loads the R and RS registers with default values. An example is shown below: |
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OpenOC1( OC_ON | OC_TIMER2_SRC | OC_PWM_FAULT_PIN_DISABLE, 0, 0); |
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The different configurations are shown below. If not specified, the default configuration is used. |
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{| border="1" |
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|- style="background:#efefef;" |
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| OC_ON || Turns the Module ON |
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|- |
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| OC_OFF || Default - Turns the Module Off |
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|} |
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==Unidirectional Motor Control== |
==Unidirectional Motor Control== |
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This section will detail how to set up a simple program and circuit to control a motor using a PIC microcontroller and PWM. |
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===Sample Code=== |
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Revision as of 16:30, 29 July 2009
Pulse Width Modulation, or PWM, is a technique used to vary the average magnitude of a signal by changing its duty cycle (the proportion of time that a signal is active or "high"). For a more in-depth introduction to PWM motor control click here.
PWM for PIC32 is discussed in more detail in the Microchip Output Compare documention.
Available Pins
The pins available for PWM are 5 input pins (OC1, OC2, OC3, OC4, and OC5) and 2 output pins (OCFA and OCFB). The output pins are for fault pin protection.
General Approach
PWM can be set up by either changing the directly altering register bits or using the functions in outcompare.h (a header file included in the peripheral library (plib.h). The latter case is more straightforward and easier. This wiki describes how to use the outcompare functions. The register bits approach is described in detail in theMicrochip Output Compare documention.
There are three main functions that are used for PWM.
void OpenOCX( config, value1, value2)
where X is the module that you want to use (1-5). This function configures the OCX module and loads the R and RS registers with default values. An example is shown below:
OpenOC1( OC_ON | OC_TIMER2_SRC | OC_PWM_FAULT_PIN_DISABLE, 0, 0);
The different configurations are shown below. If not specified, the default configuration is used.
| OC_ON | Turns the Module ON |
| OC_OFF | Default - Turns the Module Off |
Unidirectional Motor Control
This section will detail how to set up a simple program and circuit to control a motor using a PIC microcontroller and PWM.
