Unit PWM
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Description
Ultibo PWM Interface unit
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
PWM_*
PWM_NAME_PREFIX = 'PWM';
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Name prefix for PWM Devices |
PWM_TYPE_*
PWM_TYPE_NONE = 0;
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PWM_TYPE_MAX = 0;
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PWM_STATE_*
PWM_STATE_DISABLED = 0;
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PWM_STATE_ENABLED = 1;
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PWM_FLAG_*
PWM_FLAG_NONE = $00000000;
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PWM_FLAG_GPIO = $00000001;
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Device supports Get/Set GPIO |
PWM_FLAG_MODE = $00000002;
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Device supports Get/Set Mode |
PWM_FLAG_RANGE = $00000004;
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Device supports Get/Set Range |
PWM_FLAG_FREQUENCY = $00000008;
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Device supports Get/Set Frequency |
PWM_FLAG_POLARITY = $00000010;
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Device supports Get/Set Polarity |
PWM_MODE_*
PWM_MODE_MARKSPACE = 0;
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Standard PWM Mark/Space mode |
PWM_MODE_BALANCED = 1;
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Balanced mode (Device specific) |
PWM_MODE_SERIALIZED = 2;
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Serialized mode (Device specific) |
PWM_MODE_MAX = 2;
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PWM_POLARITY_*
PWM_POLARITY_NORMAL = 0;
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PWM_POLARITY_INVERSE = 1;
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PWM_POLARITY_MAX = 1;
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PWM_LOG_*
PWM_LOG_LEVEL_DEBUG = LOG_LEVEL_DEBUG;
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PWM debugging messages |
PWM_LOG_LEVEL_INFO = LOG_LEVEL_INFO;
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PWM informational messages, such as a device being attached or detached |
PWM_LOG_LEVEL_WARN = LOG_LEVEL_WARN;
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PWM warning messages |
PWM_LOG_LEVEL_ERROR = LOG_LEVEL_ERROR;
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PWM error messages |
PWM_LOG_LEVEL_NONE = LOG_LEVEL_NONE;
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No PWM messages |
Type definitions
PWM properties
PPWMProperties = ^TPWMProperties;
TPWMProperties = record
Flags:LongWord;
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Device flags (eg PWM_FLAG_MODE) |
GPIO:LongWord;
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Mode:LongWord;
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Range:LongWord;
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Frequency:LongWord;
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Polarity:LongWord;
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DutyNS:LongWord;
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PeriodNS:LongWord;
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MinPeriod:LongWord;
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PWM enumeration callback
TPWMEnumerate = function(PWM:PPWMDevice; Data:Pointer):LongWord;
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PWM notification callback
TPWMNotification = function(Device:PDevice; Data:Pointer; Notification:LongWord):LongWord;
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PWM device start
TPWMDeviceStart = function(PWM:PPWMDevice):LongWord;
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PWM device stop
TPWMDeviceStop = function(PWM:PPWMDevice):LongWord;
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PWM device write
TPWMDeviceWrite = function(PWM:PPWMDevice; Value:LongWord):LongWord;
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PWM device get GPIO
TPWMDeviceGetGPIO = function(PWM:PPWMDevice):LongWord;
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PWM device set GPIO
TPWMDeviceSetGPIO = function(PWM:PPWMDevice; GPIO:LongWord):LongWord;
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PWM device get mode
TPWMDeviceGetMode = function(PWM:PPWMDevice):LongWord;
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PWM device set mode
TPWMDeviceSetMode = function(PWM:PPWMDevice; Mode:LongWord):LongWord;
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PWM device get range
TPWMDeviceGetRange = function(PWM:PPWMDevice):LongWord;
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PWM device set range
TPWMDeviceSetRange = function(PWM:PPWMDevice; Range:LongWord):LongWord;
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PWM device get frequency
TPWMDeviceGetFrequency = function(PWM:PPWMDevice):LongWord;
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PWM device set frequency
TPWMDeviceSetFrequency = function(PWM:PPWMDevice; Frequency:LongWord):LongWord;
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PWM device get polarity
TPWMDeviceGetPolarity = function(PWM:PPWMDevice):LongWord;
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PWM device set polarity
TPWMDeviceSetPolarity = function(PWM:PPWMDevice; Polarity:LongWord):LongWord;
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PWM device configure
TPWMDeviceConfigure = function(PWM:PPWMDevice; DutyNS,PeriodNS:LongWord):LongWord;
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PWM device get properties
TPWMDeviceGetProperties = function(PWM:PPWMDevice; Properties:PPWMProperties):LongWord;
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PWM device
PPWMDevice = ^TPWMDevice;
TPWMDevice = record
Device Properties | |
Device:TDevice;
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The Device entry for this PWM |
PWM Properties | |
PWMId:LongWord;
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Unique Id of this PWM in the PWM table |
PWMState:LongWord;
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PWM state (eg PWM_STATE_ENABLED) |
DeviceStart:TPWMDeviceStart;
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A Device specific DeviceStart method implementing the standard PWM device interface (Mandatory) |
DeviceStop:TPWMDeviceStop;
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A Device specific DeviceStop method implementing the standard PWM device interface (Mandatory) |
DeviceWrite:TPWMDeviceWrite;
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A Device specific DeviceWrite method implementing the standard PWM device interface (Mandatory) |
DeviceGetGPIO:TPWMDeviceGetGPIO;
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A Device specific DeviceGetGPIO method implementing the standard PWM device interface (Or nil if the operation is not supported) |
DeviceSetGPIO:TPWMDeviceSetGPIO;
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A Device specific DeviceSetGPIO method implementing the standard PWM device interface (Or nil if the operation is not supported) |
DeviceGetMode:TPWMDeviceGetMode;
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A Device specific DeviceGetMode method implementing the standard PWM device interface (Or nil if the operation is not supported) |
DeviceSetMode:TPWMDeviceSetMode;
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A Device specific DeviceSetMode method implementing the standard PWM device interface (Or nil if the operation is not supported) |
DeviceGetRange:TPWMDeviceGetRange;
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A Device specific DeviceGetRange method implementing the standard PWM device interface (Or nil if the operation is not supported) |
DeviceSetRange:TPWMDeviceSetRange;
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A Device specific DeviceSetRange method implementing the standard PWM device interface (Or nil if the operation is not supported) |
DeviceGetFrequency:TPWMDeviceGetFrequency;
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A Device specific DeviceGetFrequency method implementing the standard PWM device interface (Or nil if the operation is not supported) |
DeviceSetFrequency:TPWMDeviceSetFrequency;
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A Device specific DeviceSetFrequency method implementing the standard PWM device interface (Or nil if the operation is not supported) |
DeviceGetPolarity:TPWMDeviceGetPolarity;
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A Device specific DeviceGetPolarity method implementing the standard PWM device interface (Or nil if the operation is not supported) |
DeviceSetPolarity:TPWMDeviceSetPolarity;
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A Device specific DeviceSetPolarity method implementing the standard PWM device interface (Or nil if the operation is not supported) |
DeviceConfigure:TPWMDeviceConfigure;
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A Device specific DeviceConfigure method implementing the standard PWM device interface (Mandatory) |
DeviceGetProperties:TPWMDeviceGetProperties;
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A Device specific DeviceGetProperties method implementing the standard PWM device interface (Or nil if the default method is suitable) |
Statistics Properties | |
GetCount:LongWord;
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SetCount:LongWord;
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WriteCount:LongWord;
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ConfigCount:LongWord;
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Driver Properties | |
Lock:TMutexHandle;
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Device lock |
GPIO:LongWord;
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GPIO Pin |
Mode:LongWord;
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Device Mode |
Range:LongWord;
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Device Range |
Frequency:LongWord;
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Clock Frequency |
Polarity:LongWord;
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Output Polarity |
DutyNS:LongWord;
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Duty Nanoseconds |
PeriodNS:LongWord;
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Period Nanonseconds |
Properties:TPWMProperties;
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Device properties |
Internal Properties | |
Prev:PPWMDevice;
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Previous entry in PWM table |
Next:PPWMDevice;
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Next entry in PWM table |
Public variables
PWM logging
PWM_DEFAULT_LOG_LEVEL:LongWord = PWM_LOG_LEVEL_DEBUG;
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Minimum level for PWM messages. Only messages with level greater than or equal to this will be printed. |
PWM_LOG_ENABLED:Boolean;
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Function declarations
Initialization functions
procedure PWMInit;
Note | Called only during system startup |
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PWM functions
function PWMDeviceStart(PWM:PPWMDevice):LongWord;
PWM | The PWM device to start |
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Return | ERROR_SUCCESS if completed or another error code on failure |
function PWMDeviceStop(PWM:PPWMDevice):LongWord;
PWM | The PWM device to stop |
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Return | ERROR_SUCCESS if completed or another error code on failure |
function PWMDeviceWrite(PWM:PPWMDevice; Value:LongWord):LongWord;
PWM | The PWM device to write to |
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Value | The value to write |
Return | ERROR_SUCCESS if completed or another error code on failure |
Note | The exact meaning of value may depend on the device and other configured options, in many cases the value will represent the "on" time of each pulse with regard to the duty cycle of the waveform output by the device. |
function PWMDeviceGetGPIO(PWM:PPWMDevice):LongWord;
PWM | The PWM device to get the GPIO pin from |
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Return | The current GPIO pin or GPIO_PIN_UNKNOWN on failure |
function PWMDeviceSetGPIO(PWM:PPWMDevice; GPIO:LongWord):LongWord;
PWM | The PWM device to set the GPIO pin for |
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GPIO | The GPIO pin to set (eg GPIO_PIN_12) |
Return | ERROR_SUCCESS if completed or another error code on failure |
function PWMDeviceGetMode(PWM:PPWMDevice):LongWord;
PWM | The PWM device to get the mode from |
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Return | The current mode or a default value of PWM_MODE_MARKSPACE |
function PWMDeviceSetMode(PWM:PPWMDevice; Mode:LongWord):LongWord;
PWM | The PWM device to set the mode for |
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Mode | The mode value to set (eg PWM_MODE_MARKSPACE) |
Return | ERROR_SUCCESS if completed or another error code on failure |
function PWMDeviceGetRange(PWM:PPWMDevice):LongWord;
PWM | The PWM device to get the range from |
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Return | The current range or 0 on failure |
function PWMDeviceSetRange(PWM:PPWMDevice; Range:LongWord):LongWord;
PWM | The PWM device to set the clock rate for |
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Range | The range value to set |
Return | ERROR_SUCCESS if completed or another error code on failure |
Note | The exact meaning of range may depend on the device and other configured options, in many cases the range will represent the period of one full cycle of the waveform output by the device. |
function PWMDeviceGetFrequency(PWM:PPWMDevice):LongWord;
PWM | The PWM device to get the clock frequency from |
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Return | The clock frequency in Hz or 0 on failure |
function PWMDeviceSetFrequency(PWM:PPWMDevice; Frequency:LongWord):LongWord;
PWM | The PWM device to set the clock frequency for |
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Frequency | The clock frequency to set in Hz |
Return | ERROR_SUCCESS if completed or another error code on failure |
function PWMDeviceGetPolarity(PWM:PPWMDevice):LongWord;
PWM | The PWM device to get the polarity from |
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Return | The current polarity or a default value of PWM_POLARITY_NORMAL |
function PWMDeviceSetPolarity(PWM:PPWMDevice; Polarity:LongWord):LongWord;
PWM | The PWM device to set the polarity for |
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Polarity | The polarity value to set (eg PWM_POLARITY_NORMAL) |
Return | ERROR_SUCCESS if completed or another error code on failure |
function PWMDeviceConfigure(PWM:PPWMDevice; DutyNS,PeriodNS:LongWord):LongWord;
PWM | The PWM device to set the configuration for |
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DutyNS | The "on" time part of the cycle (Nanoseconds) |
PeriodNS | The duration of one full cycle (Nanoseconds) |
Return | ERROR_SUCCESS if completed or another error code on failure |
function PWMDeviceProperties(PWM:PPWMDevice; Properties:PPWMProperties):LongWord; inline;
PWM | The PWM device to get properties from |
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Properties | Pointer to a TPWMProperties structure to fill in |
Return | ERROR_SUCCESS if completed or another error code on failure |
Note | Replaced by PWMDeviceGetProperties for consistency |
function PWMDeviceGetProperties(PWM:PPWMDevice; Properties:PPWMProperties):LongWord;
PWM | The PWM device to get properties from |
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Properties | Pointer to a TPWMProperties structure to fill in |
Return | ERROR_SUCCESS if completed or another error code on failure |
function PWMDeviceCreate:PPWMDevice;
Return | Pointer to new PWM entry or nil if PWM could not be created |
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function PWMDeviceCreateEx(Size:LongWord):PPWMDevice;
Size | Size in bytes to allocate for new PWM (Including the PWM entry) |
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Return | Pointer to new PWM entry or nil if PWM could not be created |
function PWMDeviceDestroy(PWM:PPWMDevice):LongWord;
Note | None documented |
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function PWMDeviceRegister(PWM:PPWMDevice):LongWord;
Note | None documented |
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function PWMDeviceDeregister(PWM:PPWMDevice):LongWord;
Note | None documented |
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function PWMDeviceFind(PWMId:LongWord):PPWMDevice;
Note | None documented |
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function PWMDeviceFindByName(const Name:String):PPWMDevice; inline;
Note | None documented |
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function PWMDeviceFindByDescription(const Description:String):PPWMDevice; inline;
Note | None documented |
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function PWMDeviceEnumerate(Callback:TPWMEnumerate; Data:Pointer):LongWord;
Note | None documented |
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function PWMDeviceNotification(PWM:PPWMDevice; Callback:TPWMNotification; Data:Pointer; Notification,Flags:LongWord):LongWord;
Note | None documented |
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RTL PWM functions
function SysPWMAvailable:Boolean;
Note | None documented |
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function SysPWMStart:LongWord;
Return | ERROR_SUCCESS if completed or another error code on failure |
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function SysPWMStop:LongWord;
Return | ERROR_SUCCESS if completed or another error code on failure |
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function SysPWMWrite(Value:LongWord):LongWord;
Value | The value to write |
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Return | ERROR_SUCCESS if completed or another error code on failure |
Note | The exact meaning of value may depend on the device and other configured options, in many cases the value will represent the "on" time of each pulse with regard to the duty cycle of the waveform output by the device. |
function SysPWMSetMode(Mode:LongWord):LongWord;
Mode | The mode value to set (eg PWM_MODE_MARKSPACE) |
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Return | ERROR_SUCCESS if completed or another error code on failure |
function SysPWMSetRange(Range:LongWord):LongWord;
Range | The range value to set |
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Return | ERROR_SUCCESS if completed or another error code on failure |
Note | The exact meaning of range may depend on the device and other configured options, in many cases the range will represent the period of one full cycle of the waveform output by the device. |
function SysPWMSetFrequency(Frequency:LongWord):LongWord;
Frequency | The frequency to set in Hz |
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Return | ERROR_SUCCESS if completed or another error code on failure |
function SysPWMConfigure(DutyNS,PeriodNS:LongWord):LongWord;
DutyNS | The "on" time part of the cycle (Nanoseconds) |
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PeriodNS | The duration of one full cycle (Nanoseconds) |
Return | ERROR_SUCCESS if completed or another error code on failure |
PWM helper functions
function PWMGetCount:LongWord;
Note | None documented |
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function PWMDeviceGetDefault:PPWMDevice;
Note | None documented |
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function PWMDeviceSetDefault(PWM:PPWMDevice):LongWord;
Note | None documented |
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function PWMDeviceCheck(PWM:PPWMDevice):PPWMDevice;
Note | None documented |
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function PWMTypeToString(PWMType:LongWord):String;
Note | None documented |
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function PWMStateToString(PWMState:LongWord):String;
Note | None documented |
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function PWMModeToString(PWMMode:LongWord):String;
Note | None documented |
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function PWMPolarityToString(PWMPolarity:LongWord):String;
Note | None documented |
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procedure PWMLog(Level:LongWord; PWM:PPWMDevice; const AText:String);
Note | None documented |
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procedure PWMLogInfo(PWM:PPWMDevice; const AText:String); inline;
Note | None documented |
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procedure PWMLogWarn(PWM:PPWMDevice; const AText:String); inline;
Note | None documented |
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procedure PWMLogError(PWM:PPWMDevice; const AText:String); inline;
Note | None documented |
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procedure PWMLogDebug(PWM:PPWMDevice; const AText:String); inline;
Note | None documented |
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