PWM Class Reference

The basic PWM function. More...

#include <hw_pwm.h>

Collaboration diagram for PWM:

Public Member Functions
	PWM (uint gpio_ch_A, uint gpio_ch_B, int step_ns, int period_us, bool phase_correct=false, bool ch_A_inverted=false, bool ch_B_inverted=false)
	Construct a new PWM object assuming free running sys_clk @125 MHz => sys_clk_period = 8 ns PERIOD = 8ns * (TOP+1)*(CSR_PH_CORRECT + 1)*(DIV_INT + (DIV_FRAC/16)) or PERIOD = 8ns * (TOP+1)*(CSR_PH_CORRECT + 1)* DIV) with DIV = step_ns/8 TOP = (period_us * 1000 /(ph*step_ns)) -1 This means the minimum step_ns is 8 ns and the maximum is 256*8ns = 2.048 us the maximum period is 2.048us*64536 = 132 ms.
void	start (bool enabled)
	start and stop the current PWM slice
void	set_width_nb_of_step (uint gpio_pin, uint16_t level)
	Set the pulse width in terms number of step object.
void	set_duty_cycle (uint gpio_pin, float duty_cycle)
	Set the pulse width in terms of duty cycle.
void	set_irq (irq_handler_t handler)
	Set the irq handler, executed each time the PWM counter wrap to 0.
void	clear_irq ()
	clear the slice IRQ

Static Public Member Functions
static void	StartTogether ()
	All the defined PWM slices will be synchronised.

Static Public Attributes
static uint32_t	slice_mask = 0x0
	a class variable that hold the slice number for the PWM object

Private Attributes
uint8_t	slice
	the hardware PWM slice of the Pico that handle this PWM signal
uint	step_ns
	the minimal pulse provided by the PWM
uint	period_us
	the period of the signal provided by PWM

Detailed Description

The basic PWM function.

Constructor & Destructor Documentation

PWM()

PWM::PWM	(	uint	gpio_ch_A,
		uint	gpio_ch_B,
		int	step_ns,
		int	period_us,
		bool	phase_correct = false,
		bool	ch_A_inverted = false,
		bool	ch_B_inverted = false )

Construct a new PWM object assuming free running sys_clk @125 MHz => sys_clk_period = 8 ns PERIOD = 8ns * (TOP+1)*(CSR_PH_CORRECT + 1)*(DIV_INT + (DIV_FRAC/16)) or PERIOD = 8ns * (TOP+1)*(CSR_PH_CORRECT + 1)* DIV) with DIV = step_ns/8 TOP = (period_us * 1000 /(ph*step_ns)) -1 This means the minimum step_ns is 8 ns and the maximum is 256*8ns = 2.048 us the maximum period is 2.048us*64536 = 132 ms.

Parameters

gpio_ch_A	channel A of the current PWM slice
gpio_ch_B	channel B=A+1 of the current PWM slice. May be configured as Input
step_ns	the minimal pulse provided by the PWM
period_us	the period of the signal provided by PWM
phase_correct	true if we want the channels symmetric.
ch_A_inverted	true is we want channel A to be active LO
ch_B_inverted	true is we want channel B to be active LO

Member Function Documentation

set_duty_cycle()

void PWM::set_duty_cycle	(	uint	gpio_pin,
		float	duty_cycle )

Set the pulse width in terms of duty cycle.

Parameters

gpio_pin	the related pin
duty_cycle	the required duty cycle

set_irq()

void PWM::set_irq

(

irq_handler_t

handler

)

Set the irq handler, executed each time the PWM counter wrap to 0.

Parameters

handler

set_width_nb_of_step()

void PWM::set_width_nb_of_step	(	uint	gpio_pin,
		uint16_t	level )

Set the pulse width in terms number of step object.

Parameters

gpio_pin	the related pin
level	the required number of steps

start()

void PWM::start

(

bool

enabled

)

start and stop the current PWM slice

Parameters

enabled

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The documentation for this class was generated from the following files:

• hw_pwm.h
• hw_pwm.cpp