oPWML Object

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Object List

Description
Operation
Properties

Examples
Related
Version History & Bug list

Description:

A Hardware Object that provides a low-speed clocked output with a variable sized pulse width.

The following table lists the size and availability of the oPWML Object.

	Object	Size	Description	A1	A2	B1	B2	C1
	oPWML	4 Bytes	Provides a low-speed Pulse-Width-Modulated output on any I/O line.			x	x	x

Operation:

An oPWML Object outputs a Pulse-Width-Modulated clock cycle on the I/O line specified by the IOLine property.

The output clock cycles at a frequency of about 550 Hz. The Pulse-Width of the logic-high portion of the clock cycle output is determined by the value of the DutyCycle property which is expressed as ratio of an 4-Bit number where 7 would be 50%

The Operate property specifies if the logic-high portion of the clock cycle output is generated. When the Operate property is set to 1, the oPWML Object starts generating and outputting the PWM clock cycle. When the Operate property is set to 0, the PWM pulses are discontinued and the specified I/O Line is set to 0-Volts.

Properties:

The following table lists the properties of the oPWML Object:

Property
Description

DutyCycle

A value that specifies the duty cycle of the PWM output.

Object Class: oNib Value Range: 0 - 15

Data Type: Numeric Default Value: 0

DutyCycle Operate Pulse Width Output

Any 0 0

0 Any 0

3 1 25%

7 1 50%

11 1 75%

15*
(see history) 1 100%

*Bug: A value of 15 does not work in firmware B1 to B2. Fixed in C1.

IOLine

A value that specifies which PWM I/O Line is used to output the PWM.

Object Class: oIOLine Value Range: 0 - 31

Data Type: Numeric Default Value: 0

Some I/O Lines have special purposes. Be sure to see oIOLine help file for details.

Invert

A value that selects if the output is inverted.

Object Class: oSelect0to1L Value Range: 0 - 1

Data Type: Numeric Default Value: 0

Availability: Added in Firmware C1

Operate Constant Description

0 cvOff
The PWM pulse is a high (5 Volt) going pulse.

1 cvOn
The PWM pulse is a low (0 Volt) going pulse.

Operate

A value that selects whether or not the PWM is outputted.

Object Class: oOperate Value Range: 0 - 1

Data Type: Numeric Default Value: 0

Operate Constant Description

0 cvOff
The PWM signal remains Low.

1 cvOn
The PWM signal outputs a high pulse with a Duty Cycle determined by the DutyCycle property.

Address

Returns a pointer to the address of the oCounter Object instance.

Object Class: oAddress Value Range: 0 - 127

Data Type: Pointer (Read Only) Default Value: Address of Object

Examples:

In the following example, the oPWML Object is used.

Visual Basic Syntax

C and Java Syntax

'This program causes 
' I/O Line 17 To 
' output a PWM signal.
' with a Duty Cycle
' that changes.

Dim A As New oPWML

Sub Main()
  A.IOLine = 31
  A.Operate = 1
  Do
    A.DutyCycle.Inc
    Delay = 10
  Loop
End Sub

//This program causes 
// I/O Line 17 To 
// output a PWM signal.
// with a Duty Cycle
// that changes.

oPWML A = New oPWML;

Void Main(Void){
  A.IOLine = 31;
  A.Operate = 1;
  Do{
    A.DutyCycle.Inc;
    Delay = 10;
  }
}

Basic Syntax

'This program causes 
' I/O Line 17 To 
' output a PWM signal.
' with a Duty Cycle
' that changes.

A As oPWML(31,,,cvOn)

Do
  A.DutyCycle.Inc
  Delay = 10
Loop