Difference between revisions of "Unit PWM"

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----
 
----
  
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''To be documented''
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<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 20px; padding-bottom: 15px;">
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<div style="font-size: 14px; padding-left: 12px;">'''PWM specific constants''' <code> PWM_* </code></div>
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<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
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{| class="wikitable" style="font-size: 14px; background: white;"
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|-
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| <code>PWM_NAME_PREFIX = 'PWM';</code>
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| Name prefix for PWM Devices
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|-
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|}
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</div></div>
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<br />
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<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 20px; padding-bottom: 15px;">
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<div style="font-size: 14px; padding-left: 12px;">'''PWM device type constants''' <code> PWM_TYPE_* </code></div>
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<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
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{| class="wikitable" style="font-size: 14px; background: white;"
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|-
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| <code>PWM_TYPE_NONE = 0;</code>
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| style="width: 50%;"|&nbsp;
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|-
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|}
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</div></div>
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<br />
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<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 20px; padding-bottom: 15px;">
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<div style="font-size: 14px; padding-left: 12px;">'''PWM device state constants''' <code> PWM_STATE_* </code></div>
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<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
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{| class="wikitable" style="font-size: 14px; background: white;"
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|-
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| <code>PWM_STATE_DISABLED = 0;</code>
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| style="width: 50%;"|&nbsp;
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|-
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| <code>PWM_STATE_ENABLED = 1;</code>
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| &nbsp;
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|-
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|}
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</div></div>
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<br />
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<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 20px; padding-bottom: 15px;">
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<div style="font-size: 14px; padding-left: 12px;">'''PWM device flag constants''' <code> PWM_FLAG_* </code></div>
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<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
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{| class="wikitable" style="font-size: 14px; background: white;"
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|-
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| <code>PWM_FLAG_NONE = $00000000;</code>
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| &nbsp;
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|-
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| <code>PWM_FLAG_GPIO = $00000001;</code>
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| Device supports Get/Set GPIO
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|-
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| <code>PWM_FLAG_MODE = $00000002;</code>
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| Device supports Get/Set Mode
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|-
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| <code>PWM_FLAG_RANGE = $00000004;</code>
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| Device supports Get/Set Range
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|-
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| <code>PWM_FLAG_FREQUENCY = $00000008;</code>
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| Device supports Get/Set Frequency
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|-
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| <code>PWM_FLAG_POLARITY = $00000010;</code>
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| Device supports Get/Set Polarity
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|-
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|}
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</div></div>
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<br />
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<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 20px; padding-bottom: 15px;">
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<div style="font-size: 14px; padding-left: 12px;">'''PWM mode value constants''' <code> PWM_MODE_* </code></div>
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<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
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{| class="wikitable" style="font-size: 14px; background: white;"
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|-
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| <code>PWM_MODE_MARKSPACE = 0;</code>
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| Standard PWM Mark / Space mode
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|-
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| <code>PWM_MODE_BALANCED = 1;</code>
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| Balanced mode (Device specific)
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|-
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| <code>PWM_MODE_SERIALIZED = 2;</code>
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| Serialized mode (Device specific)
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|-
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|}
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</div></div>
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<br />
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<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 20px; padding-bottom: 15px;">
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<div style="font-size: 14px; padding-left: 12px;">'''PWM polarity value constants''' <code> PWM_POLARITY_* </code></div>
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<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
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{| class="wikitable" style="font-size: 14px; background: white;"
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|-
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| <code>PWM_POLARITY_NORMAL = 0;</code>
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| style="width: 50%;"|&nbsp;
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|-
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| <code>PWM_POLARITY_INVERSE = 1;</code>
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| &nbsp;
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|-
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|}
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</div></div>
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<br />
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<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 20px; padding-bottom: 15px;">
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<div style="font-size: 14px; padding-left: 12px;">'''PWM logging constants''' <code> PWM_LOG_* </code></div>
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<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
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{| class="wikitable" style="font-size: 14px; background: white;"
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|-
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| <code>PWM_LOG_LEVEL_DEBUG = LOG_LEVEL_DEBUG;</code>
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| PWM debugging messages
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|-
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| <code>PWM_LOG_LEVEL_INFO = LOG_LEVEL_INFO;</code>
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| PWM informational messages, such as a device being attached or detached
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|-
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| <code>PWM_LOG_LEVEL_ERROR = LOG_LEVEL_ERROR;</code>
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| PWM error messages
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|-
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| <code>PWM_LOG_LEVEL_NONE = LOG_LEVEL_NONE;</code>
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| No PWM messages
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|-
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|}
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</div></div>
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<br />
  
 
=== Type definitions ===
 
=== Type definitions ===

Revision as of 04:55, 28 November 2016

Return to Unit Reference


Description

Pulse Width Modulation (PWM) is a technique of encoding a pulsed signal so as to control the ratio of on to off by switching the signal between on and off at a very high rate.

This on and off switching allows control of the average power supplied to the load and therefore gives fine grained control of things such as motor speeds, lamp dimming and heating elements.

PWM is also used in many low power applications as well such as controlling servo motors and can even by used for audio applications such as class D amplifiers.

This unit deals with the usage of PWM for control applications (for audio applications see the Audio unit) and provides methods to control the state, frequency, duty cycle, range and mode of PWM host controllers. Not all devices support all of these concepts so this API includes a properties function to allow obtaining information about a PWM device and its capabilities.

Constants


[Expand]
PWM specific constants PWM_*


[Expand]
PWM device type constants PWM_TYPE_*


[Expand]
PWM device state constants PWM_STATE_*


[Expand]
PWM device flag constants PWM_FLAG_*


[Expand]
PWM mode value constants PWM_MODE_*


[Expand]
PWM polarity value constants PWM_POLARITY_*


[Expand]
PWM logging constants PWM_LOG_*


Type definitions

To be documented

Public variables

To be documented

Function declarations


Initialization functions

[Expand] 
procedure PWMInit;
Description: Initialize the PWM unit and PWM device table


PWM functions

[Expand] 
function PWMDeviceStart(PWM:PPWMDevice):LongWord;
Description: Start the specified PWM device


[Expand] 
function PWMDeviceStop(PWM:PPWMDevice):LongWord;
Description: Stop the specified PWM device


[Expand] 
function PWMDeviceWrite(PWM:PPWMDevice; Value:LongWord):LongWord;
Description: Write a value to the specified PWM device


[Expand] 
function PWMDeviceGetGPIO(PWM:PPWMDevice):LongWord;
Description: Get the GPIO pin used by the specified PWM device


[Expand] 
function PWMDeviceSetGPIO(PWM:PPWMDevice; GPIO:LongWord):LongWord;
Description: Set the GPIO pin used by the specified PWM device


[Expand] 
function PWMDeviceGetMode(PWM:PPWMDevice):LongWord;
Description: Get the current mode of the specified PWM device


[Expand] 
function PWMDeviceSetMode(PWM:PPWMDevice; Mode:LongWord):LongWord;
Description: Set the current mode for the specified PWM device


[Expand] 
function PWMDeviceGetRange(PWM:PPWMDevice):LongWord;
Description: Get the current range of the specified PWM device


[Expand] 
function PWMDeviceSetRange(PWM:PPWMDevice; Range:LongWord):LongWord;
Description: Set the current range for the specified PWM device


[Expand] 
function PWMDeviceGetFrequency(PWM:PPWMDevice):LongWord;
Description: Get the clock frequency of the specified PWM device


[Expand] 
function PWMDeviceSetFrequency(PWM:PPWMDevice; Frequency:LongWord):LongWord;
Description: Set the clock frequency for the specified PWM device


[Expand] 
function PWMDeviceGetPolarity(PWM:PPWMDevice):LongWord;
Description: Get the current polarity of the specified PWM device


[Expand] 
function PWMDeviceSetPolarity(PWM:PPWMDevice; Polarity:LongWord):LongWord;
Description: Set the current polarity for the specified PWM device


[Expand] 
function PWMDeviceConfigure(PWM:PPWMDevice; DutyNS,PeriodNS:LongWord):LongWord;
Description: Set the configuration of the specified PWM device


[Expand] 
function PWMDeviceProperties(PWM:PPWMDevice; Properties:PPWMProperties):LongWord;
Description: Get the properties for the specified PWM device


[Expand] 
function PWMDeviceCreate:PPWMDevice;
Description: Create a new PWM entry


[Expand] 
function PWMDeviceCreateEx(Size:LongWord):PPWMDevice;
Description: Create a new PWM entry


[Expand] 
function PWMDeviceDestroy(PWM:PPWMDevice):LongWord;
Description: Destroy an existing PWM entry


[Expand] 
function PWMDeviceRegister(PWM:PPWMDevice):LongWord;
Description: Register a new PWM in the PWM table


[Expand] 
function PWMDeviceDeregister(PWM:PPWMDevice):LongWord;
Description: Deregister a PWM from the PWM table


[Expand] 
function PWMDeviceFind(PWMId:LongWord):PPWMDevice;
Description: To be documented


[Expand] 
function PWMDeviceFindByName(const Name:String):PPWMDevice; inline;
Description: To be documented


[Expand] 
function PWMDeviceFindByDescription(const Description:String):PPWMDevice; inline;
Description: To be documented


[Expand] 
function PWMDeviceEnumerate(Callback:TPWMEnumerate; Data:Pointer):LongWord;
Description: To be documented


[Expand] 
function PWMDeviceNotification(PWM:PPWMDevice; Callback:TPWMNotification; Data:Pointer; Notification,Flags:LongWord):LongWord;
Description: To be documented


RTL PWM functions

[Expand] 
function SysPWMAvailable:Boolean;
Description: Check if a PWM device is available


[Expand] 
function SysPWMStart:LongWord;
Description: Start the default PWM device


[Expand] 
function SysPWMStop:LongWord;
Description: Stop the default PWM device


[Expand] 
function SysPWMWrite(Value:LongWord):LongWord;
Description: Write a value to the default PWM device


[Expand] 
function SysPWMSetMode(Mode:LongWord):LongWord;
Description: Set the mode for the default PWM device


[Expand] 
function SysPWMSetRange(Range:LongWord):LongWord;
Description: Set the range for the default PWM device


[Expand] 
function SysPWMSetFrequency(Frequency:LongWord):LongWord;
Description: Set the clock frequency for the default PWM device


[Expand] 
function SysPWMConfigure(DutyNS,PeriodNS:LongWord):LongWord;
Description: Set the configuration of the default PWM device


PWM helper functions

[Expand] 
function PWMGetCount:LongWord; inline;
Description: Get the current PWM count


[Expand] 
function PWMDeviceGetDefault:PPWMDevice; inline;
Description: Get the current default PWM device


[Expand] 
function PWMDeviceSetDefault(PWM:PPWMDevice):LongWord;
Description: Set the current default PWM device


[Expand] 
function PWMDeviceCheck(PWM:PPWMDevice):PPWMDevice;
Description: Check if the supplied PWM is in the PWM table


[Expand] 
procedure PWMLog(Level:LongWord; PWM:PPWMDevice; const AText:String);
Description: To be documented


[Expand] 
procedure PWMLogInfo(PWM:PPWMDevice; const AText:String); inline;
Description: To be documented


[Expand] 
procedure PWMLogError(PWM:PPWMDevice; const AText:String); inline;
Description: To be documented


[Expand] 
procedure PWMLogDebug(PWM:PPWMDevice; const AText:String); inline;
Description: To be documented


Return to Unit Reference

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