Difference between revisions of "Unit PWM"

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Line 5: Line 5:
 
----
 
----
  
−
'''Ultibo PWM interface unit'''
+
'''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.  
 
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.  
Line 37: Line 37:
 
| <code>PWM_TYPE_NONE = 0;</code>
 
| <code>PWM_TYPE_NONE = 0;</code>
 
| style="width: 50%;"|&nbsp;
 
| style="width: 50%;"|&nbsp;
 +
|-
 +
|colspan="2"|&nbsp;
 +
|-
 +
| <code>PWM_TYPE_MAX = 0;</code>
 +
| &nbsp;
 
|-
 
|-
 
|}
 
|}
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| <code>PWM_MODE_SERIALIZED = 2;</code>
 
| <code>PWM_MODE_SERIALIZED = 2;</code>
 
| Serialized mode (Device specific)
 
| Serialized mode (Device specific)
 +
|-
 +
|colspan="2"|&nbsp;
 +
|-
 +
| <code>PWM_MODE_MAX = 2;</code>
 +
| &nbsp;
 
|-
 
|-
 
|}
 
|}
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|-
 
|-
 
| <code>PWM_POLARITY_INVERSE = 1;</code>
 
| <code>PWM_POLARITY_INVERSE = 1;</code>
 +
| &nbsp;
 +
|-
 +
|colspan="2"|&nbsp;
 +
|-
 +
| <code>PWM_POLARITY_MAX = 1;</code>
 
| &nbsp;
 
| &nbsp;
 
|-
 
|-
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| <code>PWM_LOG_LEVEL_INFO = LOG_LEVEL_INFO;</code>
 
| <code>PWM_LOG_LEVEL_INFO = LOG_LEVEL_INFO;</code>
 
| PWM informational messages, such as a device being attached or detached
 
| PWM informational messages, such as a device being attached or detached
 +
|-
 +
| <code>PWM_LOG_LEVEL_WARN = LOG_LEVEL_WARN;</code>
 +
| PWM warning messages
 
|-
 
|-
 
| <code>PWM_LOG_LEVEL_ERROR = LOG_LEVEL_ERROR;</code>
 
| <code>PWM_LOG_LEVEL_ERROR = LOG_LEVEL_ERROR;</code>
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|}
 
|}
  
−
'''PWM device properties'''
+
'''PWM device get properties'''
 
   
 
   
 
{| class="wikitable" style="font-size: 14px; text-align: left; width: 100%; height: 50px;"
 
{| class="wikitable" style="font-size: 14px; text-align: left; width: 100%; height: 50px;"
 
|-
 
|-
−
| <code>TPWMDeviceProperties = function(PWM:PPWMDevice; Properties:PPWMProperties):LongWord;</code>
+
| <code>TPWMDeviceGetProperties = function(PWM:PPWMDevice; Properties:PPWMProperties):LongWord;</code>
 
| style="width: 40%;"|
 
| style="width: 40%;"|
 
|-
 
|-
Line 393: Line 411:
 
| A Device specific DeviceConfigure method implementing the standard PWM device interface (Mandatory)
 
| A Device specific DeviceConfigure method implementing the standard PWM device interface (Mandatory)
 
|-
 
|-
−
| <code>DeviceProperties:TPWMDeviceProperties;</code>
+
| <code>DeviceGetProperties:TPWMDeviceGetProperties;</code>
−
| A Device specific DeviceProperties method implementing the standard PWM device interface (Or nil if the default method is suitable)
+
| A Device specific DeviceGetProperties method implementing the standard PWM device interface (Or nil if the default method is suitable)
 
|-
 
|-
 
|colspan="2"|''Statistics Properties''
 
|colspan="2"|''Statistics Properties''
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Note'''
+
! Note
 
| Called only during system startup
 
| Called only during system startup
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to start
 
| The PWM device to start
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to stop
 
| The PWM device to stop
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to write to
 
| The PWM device to write to
 
|-
 
|-
−
! '''Value'''
+
! Value
 
| The value to write
 
| The value to write
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
−
! '''Note'''
+
! 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
+
| 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.
 
|-
 
|-
 
|}
 
|}
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to get the GPIO pin from
 
| The PWM device to get the GPIO pin from
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| The current GPIO pin or GPIO_PIN_UNKNOWN on failure
 
| The current GPIO pin or GPIO_PIN_UNKNOWN on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to set the GPIO pin for
 
| The PWM device to set the GPIO pin for
 
|-
 
|-
−
! '''GPIO'''
+
! GPIO
 
| The GPIO pin to set (eg GPIO_PIN_12)
 
| The GPIO pin to set (eg GPIO_PIN_12)
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to get the mode from
 
| The PWM device to get the mode from
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| The current mode or a default value of PWM_MODE_MARKSPACE
 
| The current mode or a default value of PWM_MODE_MARKSPACE
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to set the mode for
 
| The PWM device to set the mode for
 
|-
 
|-
−
! '''Mode'''
+
! Mode
 
| The mode value to set (eg PWM_MODE_MARKSPACE)
 
| The mode value to set (eg PWM_MODE_MARKSPACE)
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to get the range from
 
| The PWM device to get the range from
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| The current range or 0 on failure
 
| The current range or 0 on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to set the clock rate for
 
| The PWM device to set the clock rate for
 
|-
 
|-
−
! '''Range'''
+
! Range
 
| The range value to set
 
| The range value to set
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
−
! '''Note'''
+
! 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
+
| 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.
 
|-
 
|-
 
|}
 
|}
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to get the clock frequency from
 
| The PWM device to get the clock frequency from
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| The clock frequency in Hz or 0 on failure
 
| The clock frequency in Hz or 0 on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to set the clock frequency for
 
| The PWM device to set the clock frequency for
 
|-
 
|-
−
! '''Frequency'''
+
! Frequency
 
| The clock frequency to set in Hz
 
| The clock frequency to set in Hz
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to get the polarity from
 
| The PWM device to get the polarity from
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| The current polarity or a default value of PWM_POLARITY_NORMAL
 
| The current polarity or a default value of PWM_POLARITY_NORMAL
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to set the polarity for
 
| The PWM device to set the polarity for
 
|-
 
|-
−
! '''Polarity'''
+
! Polarity
 
| The polarity value to set (eg PWM_POLARITY_NORMAL)
 
| The polarity value to set (eg PWM_POLARITY_NORMAL)
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to set the configuration for
 
| The PWM device to set the configuration for
 
|-
 
|-
−
! '''DutyNS'''
+
! DutyNS
 
| The "on" time part of the cycle (Nanoseconds)
 
| The "on" time part of the cycle (Nanoseconds)
 
|-
 
|-
−
! '''PeriodNS'''
+
! PeriodNS
 
| The duration of one full cycle (Nanoseconds)
 
| The duration of one full cycle (Nanoseconds)
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
Line 733: Line 751:
 
<br />
 
<br />
 
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
−
<pre style="border: 0; padding-bottom:0px;">function PWMDeviceProperties(PWM:PPWMDevice; Properties:PPWMProperties):LongWord;</pre>
+
<pre style="border: 0; padding-bottom:0px;">function PWMDeviceProperties(PWM:PPWMDevice; Properties:PPWMProperties):LongWord; inline;</pre>
 
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Get the properties for the specified PWM device</div>
 
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Get the properties for the specified PWM device</div>
 
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''PWM'''
+
! PWM
 
| The PWM device to get properties from
 
| The PWM device to get properties from
 
|-
 
|-
−
! '''Properties'''
+
! Properties
 
| Pointer to a TPWMProperties structure to fill in
 
| Pointer to a TPWMProperties structure to fill in
 
|-
 
|-
−
! '''Return'''
+
! Return
 +
| ERROR_SUCCESS if completed or another error code on failure
 +
|-
 +
! Note
 +
| Replaced by PWMDeviceGetProperties for consistency
 +
|-
 +
|}
 +
</div></div>
 +
<br />
 +
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 +
<pre style="border: 0; padding-bottom:0px;">function PWMDeviceGetProperties(PWM:PPWMDevice; Properties:PPWMProperties):LongWord;</pre>
 +
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Get the properties for the specified PWM device</div>
 +
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 +
{| class="wikitable" style="font-size: 14px; background: white;"
 +
|-
 +
! PWM
 +
| The PWM device to get properties from
 +
|-
 +
! Properties
 +
| Pointer to a TPWMProperties structure to fill in
 +
|-
 +
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| Pointer to new PWM entry or nil if PWM could not be created
 
| Pointer to new PWM entry or nil if PWM could not be created
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Size'''
+
! Size
 
| Size in bytes to allocate for new PWM (Including the PWM entry)
 
| Size in bytes to allocate for new PWM (Including the PWM entry)
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| Pointer to new PWM entry or nil if PWM could not be created
 
| Pointer to new PWM entry or nil if PWM could not be created
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Note'''
+
! Note
 
| None documented
 
| None documented
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Note'''
+
! Note
 
| None documented
 
| None documented
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Note'''
+
! Note
 
| None documented
 
| None documented
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Note'''
+
! Note
 
| None documented
 
| None documented
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Note'''
+
! Note
 
| None documented
 
| None documented
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Note'''
+
! Note
 
| None documented
 
| None documented
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Note'''
+
! Note
 
| None documented
 
| None documented
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Note'''
+
! Note
 
| None documented
 
| None documented
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Note'''
+
! Note
 
| None documented
 
| None documented
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Value'''
+
! Value
 
| The value to write
 
| The value to write
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
−
! '''Note'''
+
! 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
+
| 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.
 
|-
 
|-
 
|}
 
|}
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Mode'''
+
! Mode
 
| The mode value to set (eg PWM_MODE_MARKSPACE)
 
| The mode value to set (eg PWM_MODE_MARKSPACE)
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Range'''
+
! Range
 
| The range value to set
 
| The range value to set
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
−
! '''Note'''
+
! 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
+
| 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.
 
|-
 
|-
 
|}
 
|}
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''Frequency'''
+
! Frequency
 
| The frequency to set in Hz
 
| The frequency to set in Hz
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
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{| class="wikitable" style="font-size: 14px; background: white;"
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
|-
 
|-
−
! '''DutyNS'''
+
! DutyNS
 
| The "on" time part of the cycle (Nanoseconds)
 
| The "on" time part of the cycle (Nanoseconds)
 
|-
 
|-
−
! '''PeriodNS'''
+
! PeriodNS
 
| The duration of one full cycle (Nanoseconds)
 
| The duration of one full cycle (Nanoseconds)
 
|-
 
|-
−
! '''Return'''
+
! Return
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
 
|-
 
|-
Line 1,000: Line 1,039:
  
 
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
 
<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
−
<pre style="border: 0; padding-bottom:0px;">function PWMGetCount:LongWord; inline;</pre>
+
<pre style="border: 0; padding-bottom:0px;">function PWMGetCount:LongWord;</pre>
 
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Get the current PWM count</div>
 
<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Get the current PWM count</div>
 
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 
<div class="mw-collapsible-content" style="text-align: left; padding-left: 5px;">
 
{| class="wikitable" style="font-size: 14px; background: white;"
 
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<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Convert a PWM type value to a string</div>
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<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Convert a PWM state value to a string</div>
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<pre style="border: 0; padding-bottom:0px;">procedure PWMLogWarn(PWM:PPWMDevice; const AText:String); inline;</pre>
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Latest revision as of 03:37, 15 December 2022

Return to Unit Reference


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 specific constants PWM_*
PWM_NAME_PREFIX = 'PWM'; Name prefix for PWM Devices


PWM device type PWM_TYPE_*
PWM_TYPE_NONE = 0;  
 
PWM_TYPE_MAX = 0;  


PWM device state PWM_STATE_*
PWM_STATE_DISABLED = 0;  
PWM_STATE_ENABLED = 1;  


PWM device flag PWM_FLAG_*
PWM_FLAG_NONE = $00000000;  
PWM_FLAG_GPIO = $00000001; Device supports Get/Set GPIO
PWM_FLAG_MODE = $00000002; Device supports Get/Set Mode
PWM_FLAG_RANGE = $00000004; Device supports Get/Set Range
PWM_FLAG_FREQUENCY = $00000008; Device supports Get/Set Frequency
PWM_FLAG_POLARITY = $00000010; Device supports Get/Set Polarity


PWM mode value PWM_MODE_*
PWM_MODE_MARKSPACE = 0; Standard PWM Mark/Space mode
PWM_MODE_BALANCED = 1; Balanced mode (Device specific)
PWM_MODE_SERIALIZED = 2; Serialized mode (Device specific)
 
PWM_MODE_MAX = 2;  


PWM polarity value PWM_POLARITY_*
PWM_POLARITY_NORMAL = 0;  
PWM_POLARITY_INVERSE = 1;  
 
PWM_POLARITY_MAX = 1;  


PWM logging PWM_LOG_*
PWM_LOG_LEVEL_DEBUG = LOG_LEVEL_DEBUG; PWM debugging messages
PWM_LOG_LEVEL_INFO = LOG_LEVEL_INFO; PWM informational messages, such as a device being attached or detached
PWM_LOG_LEVEL_WARN = LOG_LEVEL_WARN; PWM warning messages
PWM_LOG_LEVEL_ERROR = LOG_LEVEL_ERROR; PWM error messages
PWM_LOG_LEVEL_NONE = LOG_LEVEL_NONE; No PWM messages


Type definitions


PWM properties

PPWMProperties = ^TPWMProperties;

TPWMProperties = record

Flags:LongWord; Device flags (eg PWM_FLAG_MODE)
GPIO:LongWord;  
Mode:LongWord;  
Range:LongWord;  
Frequency:LongWord;  
Polarity:LongWord;  
DutyNS:LongWord;  
PeriodNS:LongWord;  
MinPeriod:LongWord;  

PWM enumeration callback

TPWMEnumerate = function(PWM:PPWMDevice; Data:Pointer):LongWord;

PWM notification callback

TPWMNotification = function(Device:PDevice; Data:Pointer; Notification:LongWord):LongWord;

PWM device start

TPWMDeviceStart = function(PWM:PPWMDevice):LongWord;

PWM device stop

TPWMDeviceStop = function(PWM:PPWMDevice):LongWord;

PWM device write

TPWMDeviceWrite = function(PWM:PPWMDevice; Value:LongWord):LongWord;

PWM device get GPIO

TPWMDeviceGetGPIO = function(PWM:PPWMDevice):LongWord;

PWM device set GPIO

TPWMDeviceSetGPIO = function(PWM:PPWMDevice; GPIO:LongWord):LongWord;

PWM device get mode

TPWMDeviceGetMode = function(PWM:PPWMDevice):LongWord;

PWM device set mode

TPWMDeviceSetMode = function(PWM:PPWMDevice; Mode:LongWord):LongWord;

PWM device get range

TPWMDeviceGetRange = function(PWM:PPWMDevice):LongWord;

PWM device set range

TPWMDeviceSetRange = function(PWM:PPWMDevice; Range:LongWord):LongWord;

PWM device get frequency

TPWMDeviceGetFrequency = function(PWM:PPWMDevice):LongWord;

PWM device set frequency

TPWMDeviceSetFrequency = function(PWM:PPWMDevice; Frequency:LongWord):LongWord;

PWM device get polarity

TPWMDeviceGetPolarity = function(PWM:PPWMDevice):LongWord;

PWM device set polarity

TPWMDeviceSetPolarity = function(PWM:PPWMDevice; Polarity:LongWord):LongWord;

PWM device configure

TPWMDeviceConfigure = function(PWM:PPWMDevice; DutyNS,PeriodNS:LongWord):LongWord;

PWM device get properties

TPWMDeviceGetProperties = function(PWM:PPWMDevice; Properties:PPWMProperties):LongWord;

PWM device

PPWMDevice = ^TPWMDevice;

TPWMDevice = record

Device Properties
Device:TDevice; The Device entry for this PWM
PWM Properties
PWMId:LongWord; Unique Id of this PWM in the PWM table
PWMState:LongWord; PWM state (eg PWM_STATE_ENABLED)
DeviceStart:TPWMDeviceStart; A Device specific DeviceStart method implementing the standard PWM device interface (Mandatory)
DeviceStop:TPWMDeviceStop; A Device specific DeviceStop method implementing the standard PWM device interface (Mandatory)
DeviceWrite:TPWMDeviceWrite; A Device specific DeviceWrite method implementing the standard PWM device interface (Mandatory)
DeviceGetGPIO:TPWMDeviceGetGPIO; A Device specific DeviceGetGPIO method implementing the standard PWM device interface (Or nil if the operation is not supported)
DeviceSetGPIO:TPWMDeviceSetGPIO; A Device specific DeviceSetGPIO method implementing the standard PWM device interface (Or nil if the operation is not supported)
DeviceGetMode:TPWMDeviceGetMode; A Device specific DeviceGetMode method implementing the standard PWM device interface (Or nil if the operation is not supported)
DeviceSetMode:TPWMDeviceSetMode; A Device specific DeviceSetMode method implementing the standard PWM device interface (Or nil if the operation is not supported)
DeviceGetRange:TPWMDeviceGetRange; A Device specific DeviceGetRange method implementing the standard PWM device interface (Or nil if the operation is not supported)
DeviceSetRange:TPWMDeviceSetRange; A Device specific DeviceSetRange method implementing the standard PWM device interface (Or nil if the operation is not supported)
DeviceGetFrequency:TPWMDeviceGetFrequency; A Device specific DeviceGetFrequency method implementing the standard PWM device interface (Or nil if the operation is not supported)
DeviceSetFrequency:TPWMDeviceSetFrequency; A Device specific DeviceSetFrequency method implementing the standard PWM device interface (Or nil if the operation is not supported)
DeviceGetPolarity:TPWMDeviceGetPolarity; A Device specific DeviceGetPolarity method implementing the standard PWM device interface (Or nil if the operation is not supported)
DeviceSetPolarity:TPWMDeviceSetPolarity; A Device specific DeviceSetPolarity method implementing the standard PWM device interface (Or nil if the operation is not supported)
DeviceConfigure:TPWMDeviceConfigure; A Device specific DeviceConfigure method implementing the standard PWM device interface (Mandatory)
DeviceGetProperties:TPWMDeviceGetProperties; A Device specific DeviceGetProperties method implementing the standard PWM device interface (Or nil if the default method is suitable)
Statistics Properties
GetCount:LongWord;  
SetCount:LongWord;  
WriteCount:LongWord;  
ConfigCount:LongWord;  
Driver Properties
Lock:TMutexHandle; Device lock
GPIO:LongWord; GPIO Pin
Mode:LongWord; Device Mode
Range:LongWord; Device Range
Frequency:LongWord; Clock Frequency
Polarity:LongWord; Output Polarity
DutyNS:LongWord; Duty Nanoseconds
PeriodNS:LongWord; Period Nanonseconds
Properties:TPWMProperties; Device properties
Internal Properties
Prev:PPWMDevice; Previous entry in PWM table
Next:PPWMDevice; Next entry in PWM table


Public variables


PWM logging

PWM_DEFAULT_LOG_LEVEL:LongWord = PWM_LOG_LEVEL_DEBUG; Minimum level for PWM messages. Only messages with level greater than or equal to this will be printed.
PWM_LOG_ENABLED:Boolean;


Function declarations


Initialization functions 

procedure PWMInit;
Description: Initialize the PWM unit and PWM device table
Note Called only during system startup


PWM functions 

function PWMDeviceStart(PWM:PPWMDevice):LongWord;
Description: Start the specified PWM device
PWM The PWM device to start
Return ERROR_SUCCESS if completed or another error code on failure 


function PWMDeviceStop(PWM:PPWMDevice):LongWord;
Description: Stop the specified PWM device
PWM The PWM device to stop
Return ERROR_SUCCESS if completed or another error code on failure 


function PWMDeviceWrite(PWM:PPWMDevice; Value:LongWord):LongWord;
Description: Write a value to the specified PWM device
PWM The PWM device to write to
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;
Description: Get the GPIO pin used by the specified PWM device
PWM The PWM device to get the GPIO pin from
Return The current GPIO pin or GPIO_PIN_UNKNOWN on failure 


function PWMDeviceSetGPIO(PWM:PPWMDevice; GPIO:LongWord):LongWord;
Description: Set the GPIO pin used by the specified PWM device
PWM The PWM device to set the GPIO pin for
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;
Description: Get the current mode of the specified PWM device
PWM The PWM device to get the mode from
Return The current mode or a default value of PWM_MODE_MARKSPACE 


function PWMDeviceSetMode(PWM:PPWMDevice; Mode:LongWord):LongWord;
Description: Set the current mode for the specified PWM device
PWM The PWM device to set the mode for
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;
Description: Get the current range of the specified PWM device
PWM The PWM device to get the range from
Return The current range or 0 on failure 


function PWMDeviceSetRange(PWM:PPWMDevice; Range:LongWord):LongWord;
Description: Set the current range for the specified PWM device
PWM The PWM device to set the clock rate for
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;
Description: Get the clock frequency of the specified PWM device
PWM The PWM device to get the clock frequency from
Return The clock frequency in Hz or 0 on failure 


function PWMDeviceSetFrequency(PWM:PPWMDevice; Frequency:LongWord):LongWord;
Description: Set the clock frequency for the specified PWM device
PWM The PWM device to set the clock frequency for
Frequency The clock frequency to set in Hz
Return ERROR_SUCCESS if completed or another error code on failure 


function PWMDeviceGetPolarity(PWM:PPWMDevice):LongWord;
Description: Get the current polarity of the specified PWM device
PWM The PWM device to get the polarity from
Return The current polarity or a default value of PWM_POLARITY_NORMAL 


function PWMDeviceSetPolarity(PWM:PPWMDevice; Polarity:LongWord):LongWord;
Description: Set the current polarity for the specified PWM device
PWM The PWM device to set the polarity for
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;
Description: Set the configuration of the specified PWM device
PWM The PWM device to set the configuration for
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;
Description: Get the properties for the specified PWM device
PWM The PWM device to get properties from
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;
Description: Get the properties for the specified PWM device
PWM The PWM device to get properties from
Properties Pointer to a TPWMProperties structure to fill in
Return ERROR_SUCCESS if completed or another error code on failure 


function PWMDeviceCreate:PPWMDevice;
Description: Create a new PWM entry
Return Pointer to new PWM entry or nil if PWM could not be created 


function PWMDeviceCreateEx(Size:LongWord):PPWMDevice;
Description: Create a new PWM entry
Size Size in bytes to allocate for new PWM (Including the PWM entry)
Return Pointer to new PWM entry or nil if PWM could not be created 


function PWMDeviceDestroy(PWM:PPWMDevice):LongWord;
Description: Destroy an existing PWM entry
Note None documented 


function PWMDeviceRegister(PWM:PPWMDevice):LongWord;
Description: Register a new PWM in the PWM table
Note None documented 


function PWMDeviceDeregister(PWM:PPWMDevice):LongWord;
Description: Deregister a PWM from the PWM table
Note None documented 


function PWMDeviceFind(PWMId:LongWord):PPWMDevice;
Description: To be documented
Note None documented 


function PWMDeviceFindByName(const Name:String):PPWMDevice; inline;
Description: To be documented
Note None documented 


function PWMDeviceFindByDescription(const Description:String):PPWMDevice; inline;
Description: To be documented
Note None documented 


function PWMDeviceEnumerate(Callback:TPWMEnumerate; Data:Pointer):LongWord;
Description: To be documented
Note None documented 


function PWMDeviceNotification(PWM:PPWMDevice; Callback:TPWMNotification; Data:Pointer; Notification,Flags:LongWord):LongWord;
Description: To be documented
Note None documented


RTL PWM functions 

function SysPWMAvailable:Boolean;
Description: Check if a PWM device is available
Note None documented 


function SysPWMStart:LongWord;
Description: Start the default PWM device
Return ERROR_SUCCESS if completed or another error code on failure 


function SysPWMStop:LongWord;
Description: Stop the default PWM device
Return ERROR_SUCCESS if completed or another error code on failure 


function SysPWMWrite(Value:LongWord):LongWord;
Description: Write a value to the default PWM device
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 SysPWMSetMode(Mode:LongWord):LongWord;
Description: Set the mode for the default PWM device
Mode The mode value to set (eg PWM_MODE_MARKSPACE)
Return ERROR_SUCCESS if completed or another error code on failure 


function SysPWMSetRange(Range:LongWord):LongWord;
Description: Set the range for the default PWM device
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 SysPWMSetFrequency(Frequency:LongWord):LongWord;
Description: Set the clock frequency for the default PWM device
Frequency The frequency to set in Hz
Return ERROR_SUCCESS if completed or another error code on failure 


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


PWM helper functions 

function PWMGetCount:LongWord;
Description: Get the current PWM count
Note None documented 


function PWMDeviceGetDefault:PPWMDevice;
Description: Get the current default PWM device
Note None documented 


function PWMDeviceSetDefault(PWM:PPWMDevice):LongWord;
Description: Set the current default PWM device
Note None documented 


function PWMDeviceCheck(PWM:PPWMDevice):PPWMDevice;
Description: Check if the supplied PWM is in the PWM table
Note None documented 


function PWMTypeToString(PWMType:LongWord):String;
Description: Convert a PWM type value to a string
Note None documented 


function PWMStateToString(PWMState:LongWord):String;
Description: Convert a PWM state value to a string
Note None documented 


function PWMModeToString(PWMMode:LongWord):String;
Description: Convert a PWM mode value to a string
Note None documented 


function PWMPolarityToString(PWMPolarity:LongWord):String;
Description: Convert a PWM polarity value to a string
Note None documented 


procedure PWMLog(Level:LongWord; PWM:PPWMDevice; const AText:String);
Description: To be documented
Note None documented 


procedure PWMLogInfo(PWM:PPWMDevice; const AText:String); inline;
Description: To be documented
Note None documented 


procedure PWMLogWarn(PWM:PPWMDevice; const AText:String); inline;
Description: To be documented
Note None documented 


procedure PWMLogError(PWM:PPWMDevice; const AText:String); inline;
Description: To be documented
Note None documented 


procedure PWMLogDebug(PWM:PPWMDevice; const AText:String); inline;
Description: To be documented
Note None documented


Return to Unit Reference

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