Component: PWM (Internal) (General Output)

Author	Matrix Ltd
Version	2.1
Category	General Output

PWM (Internal) component

Pulse Width Modulation, a versitile way of generating a digital pulse using mark / space modulation. Uses the capture compare peripherals onboard most Microcontrollers to generate accurate waveforms without any intervention from the processor. Useful for generating audio, controlling the speed of motors, brightness of LED etc.

Detailed description

No detailed description exists yet for this component

Examples

Here is a basic example to control the PWM duty based on an ADC reading.

PWMDemo

Digital PWM trace

File:PWMDigital.jpg

Here is another basic example which ramps the PWM duty cycle up and down. If the PWM output pin is connected to a LED and series resistor then the LED will smoothly transition between on bright and off.

PWM Fader

Downloadable macro reference

	ChangePeriod
Sets the overall period and prescaler of the output PWM signal.
- UINT	Period
The maximum number that will represent 100% on, PIC/AVR: 0-255 16-bit PIC: 0-65535
[[File:]] -	Prescaler
The scaler used to divide the system clock speed down to the PWM rate.
- VOID	Return

	Disable
Disables a PWM channel and allows the default output / input state to be resumed
- VOID	Return

	SetDutyCycle
Sets the PWM duty cycle in terms of on/off based on the current period setting. E.g. if period = 255 then duty of 128 is equal to 50% on and 50% off. 16-bit PIC users should use the 10bit duty function to access the full range.
- BYTE	Duty
8-bit PWM duty 0-255
- VOID	Return

	Enable
Enables a PWM channel as an output overriding the default output pin state.
- VOID	Return

	SetFrequency
Sets a PWM of the specifed frequency at a duty of 50% Ideal use is a frequency generator
- ULONG	Frequency
Enter frequency in Hz
- VOID	Return

	SetDutyCycle10Bit
PIC/AVR - Sets the full scale PWM duty cycle based on the current period setting. If period = 255 then Duty of 512 is equal to 50%. 16-bit PICs have a 16-bit period range available. If period = 65535 then Duty of 32768 is equal to 50%.
- UINT	Duty
PWM duty PIC/AVR: 0-1023 16-bit PIC: 0-65535
- VOID	Return

	Initialise
The Init macro must be called once to initialise the Graphical LCD display before any other Graphical LCD component macros are called.
- VOID	Return

	Initialise
The Init macro must be called once to initialise the Graphical LCD display before any other Graphical LCD component macros are called.
- VOID	Return

	Initialise
The Init macro must be called once to initialise the Graphical LCD display before any other Graphical LCD component macros are called.
- VOID	Return

	Initialise
Resets and initialises the Internet E-Block. It sets up the gateway address, subnet mask, device IP address and device MAC address as defined in the properties of the Flowcode component. This macro must be called before any other TCP_IP component macros
- VOID	Return

	Initialise
Resets and initialises the Internet E-Block. It sets up the gateway address, subnet mask, device IP address and device MAC address as defined in the properties of the Flowcode component. This macro must be called before any other TCP_IP component macros
- VOID	Return

	Initialise
Resets and initialises the Internet E-Block. It sets up the gateway address, subnet mask, device IP address and device MAC address as defined in the properties of the Flowcode component. This macro must be called before any other TCP_IP component macros
- VOID	Return

	MODPMSHAPE
Sets PM waveform shape to; 0 = SINE, 1 = SQUARE, 2 = RAMPUP, 3 = RAMPDN, 4 = TRIANG, 5 = NOISE, 6 = DC, 7 = SINC, 8 = EXPRISE, 9 = LOGRISE, 10 = ARB1, 11 = ARB2, 12 = ARB3, 13= ARB4.
- BYTE	Shape
Sets PM waveform shape (1 = SINE, 2 = SQUARE, 3 = RAMPUP, 4 = RAMPDN, 5 = TRIANG, 6 = NOISE, 7 = DC, 8 = SINC, 9 = EXPRISE, 10 = LOGRISE, 11 = ARB1, 12 = ARB2, 13 = ARB3, 14= ARB4).
- VOID	Return

	ARB4
Loads the binary-data to an existing arbitrary waveform memory location ARB4.
- BYTE	Waveform
- VOID	Return

	CLKSRRet
Returns the clock source <INT> or <EXT>.
[[File:]] -	Return

	MODPMDEV
Sets PM waveform deviation to <nrf> degrees. (Lower limit: -360° - Upper limit: 360°).
[[File:]] -	Degrees
Sets PM waveform deviation in degrees (-360 - 360).
- VOID	Return

	MSTLOCK
Sends signal to SLAVE generator to get synchronised
- VOID	Return

	HILVL
Sets the amplitude-high-level to <nrf> Volts. (Lower limit: -0.490 V - Upper limit: 5.000 V).
[[File:]] -	HighLevel
Sets the amplitude-high-level in Volts(V) (-0.490 V - 5.000 V).
- VOID	Return

	ARB3
Loads the binary-data to an existing arbitrary waveform memory location ARB3.
- UINT	Waveform
- VOID	Return

	WAVE
Sets the waveform type. 0 = SINE, 1 = SQUARE, 2 = RAMP, 3 = TRIANG, 4 = PULSE, 5 = NOISE, 6 = ARB
- BYTE	WaveType
0 = SINE, 1 = SQUARE, 2 = RAMP, 3 = TRIANG, 4 = PULSE, 5 = NOISE, 6 = ARB.
- VOID	Return

	CALADJ
Adjust the selected calibration value by <nrf> (Lower limit: -100 - Upper limit: 100).
[[File:]] -	Calibrate
Adjust the selected calibration value (-100 - 100).
- VOID	Return

	STBRet
Returns the value of the Status Byte Register in <nr1> numeric format.
- BYTE	Return

	ARB2
Loads the binary-data to an existing arbitrary waveform memory location ARB2.
- UINT	Waveform
- VOID	Return

	EERRet
Query and clear execution error number register.
- STRING	Return

	MODFMSRC
Sets FM waveform source to; 0 INT, 1 = EXT.
[[File:]] -	Source
Sets FM waveform source (0 = INT, 1 = EXT).
- VOID	Return

	MODAMFREQ
Sets AM waveform frequency to <nrf> Hz. (Lower limit: 1uHz - Upper limit: 20kHz).
[[File:]] -	Frequency
Sets AM waveform frequency in Hertz(Hz) (1uHz - 20kHz).
- VOID	Return

	ESE
Sets the Standard Event Status Enable Register to the value of <nrf>.
- BYTE	Value
Value of register 0-255
- VOID	Return

	ARB1
Loads the binary-data to an existing arbitrary waveform memory location ARB1.
- UINT	Waveform
16 Bit binary number for arbitrary waveform.
- VOID	Return

	ARB4DEFRet
Returns user specified waveform name, waveform pint interpolation state and waveform length of ARB4.
- STRING	Return

	CLS
Clears status byte register of the interface.
- VOID	Return

	MSTRELOCK
Resynchronises the two generators in MASTER-SLAVE mode.
- VOID	Return

	NOISLVL
Sets the output noise level to <nr1> %. (Lower limit: 0% - Upper limit: 50%)
- BYTE	Percent
Sets the output noise level in percent. (0 - 50)
- VOID	Return

	LOCKMODE
Sets the synchronising mode to; 0 = MASTER, 1 = SLAVE, 2 = INDEP.
- BYTE	Mode
Sets the synchronising mode (0 = MASTER, 1 = SLAVE, 2 = INDEP).
- VOID	Return

	ADDRESSRet
Returns the instruments address
[[File:]] -	Return

	MODPMSRC
Sets PM waveform source to; 0 INT, 1 = EXT.
[[File:]] -	Source
Sets PM waveform source (0 = INT, 1 = EXT).
- VOID	Return

	MODPWMSRC
Sets PWM waveform source to; 0 = INT, 1 = EXT.
[[File:]] -	Source
Sets PWM waveform source (0 = INT, 1 = EXT).
- VOID	Return

	MOD
Sets modulation to; 0 = OFF, 1 = AM, 2 = FM, 3 = PM, 4 = FSK, 5 = PWM.
- BYTE	Modulation
Sets modulation (0 = OFF, 1 = AM, 2 = FM, 3 = PM, 4 = FSK, 5 = PWM).
- VOID	Return

	ISTRet
Returns IST local message as defined by IEEE Std. 488.2. The syntax of the response is 0<rmt>, if the local message is false, or 1<rmt>, if the local message is true.
[[File:]] -	Return

	LRNRet
Returns the complete setup of the instrument as a binary data block
[[File:]] -	Return

	OPCRet
Query Operation Complete status. The response is always 1<rmt> and will be available immediately the command is executed because all commands are sequential.
[[File:]] -	Return

	SWPTYPE
Sets the sweep type to; 0 = LINUP, 1 = LINDN, 2 = LINUPDN, 3 = LINDNUP, 4 = LOGUP, 5 = LOGDN, 6 = LOGUPDN, 7 = LOGDNUP.
- BYTE	Type
Set the sweep type (0 = LINUP, 1 = LINDN, 2 = LINUPDN, 3 = LINDNUP, 4 = LOGUP, 5 = LOGDN, 6 = LOGUPDN, 7 = LOGDNUP).
- VOID	Return

	PULSRANGE
Sets PWM waveform source to <1>, <2> or <3>; 1 = 1, 2 = 2, 3 = 3.
- BYTE	Range
Sets the pulse rise and fall range. (1, 2 or 3)
- VOID	Return

	TSTRet
The generator has no self test capability and the response is always 0 <rmt>.
[[File:]] -	Return

	BSTTRGPOL
Sets the burst trigger slope to; 0 = POS, 1 = NEG.
[[File:]] -	Slope
Set the burst trigger slope (0 = POS, 1 = NEG).
- VOID	Return

	ARB3Ret
Returns the binary-data from an existing abbitrary wavefrom memory location.
- UINT	Return

	BSTPHASE
Sets the burst phase to <nrf> degrees. (Lower limit: -360 - Upper limit: 360)
[[File:]] -	Degrees
Sets the burst phase in degrees (-360 - 360)
- VOID	Return

	IDNRet
Returns the instrument identification. The IDN is saved to the variable passed from the function 'ReturnIDN'. The return parameter is TRUE when the IDN is successfully returned.
- STRING	ReturnIDN
- STRING	Return

	SWPTRGPER
Sets the sweep trigger period to <nrf> seconds
[[File:]] -	Seconds
Set the sweep trigger period in seconds.
- VOID	Return

	PULSDLY
Sets the waveform delay to <nrf> sec
[[File:]] -	Sec
- VOID	Return

	Initialise
Opens the COM port ready for communications.
- VOID	Return

Property reference

	Properties
	PWM Timer
Timer associated with PWM to drive the output. Warning - All PWM channels linked to the same timer will share the same period and prescaler settings.
	Period Overflow
Allows the user to change the number of counts for the whole PWM period. Note that all PWM channels based on the same timer will share the same period overflow. PIC/AVR Range: 0 - 255 16-bit PIC Range: 0 - 65535
	Prescaler
Allows the user to change the number of program cycles per PWM cycle count. Note that all PWM channels based on the same timer will share the same prescaler.
	Period (us)
Displays the length of time to complete one PWM cycle.
	Frequency (Hz)
	Frequency (KHz)
Displays the frequency of PWM cycles per second.
	Required Frequency (Hz)
Type in your required frequency in Hz and the component will automatically calculate the best prescaler and period to acheive the frequency with the maximum possible resolution.
	Calculated Frequency (Hz)
The frequency we have ended up acheiving using the calculated period and prescaler
	Calculated Period
The suggested period setting to use to acheive the calculated frequency.
	Calculated Prescaler
The suggested prescaler setting to use to acheive the calculated frequency.
	Apply To Defaults
Applies the calculated period and prescaler settings to the PWM component default settings.
	Connections
	Channel
Selects which PWM channel the component is connected to.
	Alternative pin
Allows an alternate pin to be used if available. Note that on some devices you will also have to change this setting in the device configuration.
	PWM Pin
Specifies the pin assigned to the PWM channel selected
	Remap Pin
Allows the PWM hardware pin to be reassigned to another pin
	Simulations
	Representation
Edits how the PWM is shown on the simulation panel.