PWM

Collaboration diagram for PWM:

Data Structures
struct	rt_pwm_configuration
struct	rt_pwm_ops
struct	rt_device_pwm

Functions
rt_err_t	rt_device_pwm_register (struct rt_device_pwm *device, const char *name, const struct rt_pwm_ops *ops, const void *user_data)
rt_err_t	rt_pwm_enable (struct rt_device_pwm *device, int channel)
rt_err_t	rt_pwm_disable (struct rt_device_pwm *device, int channel)
rt_err_t	rt_pwm_set (struct rt_device_pwm *device, int channel, rt_uint32_t period, rt_uint32_t pulse)
rt_err_t	rt_pwm_set_period (struct rt_device_pwm *device, int channel, rt_uint32_t period)
rt_err_t	rt_pwm_set_pulse (struct rt_device_pwm *device, int channel, rt_uint32_t pulse)
rt_err_t	rt_pwm_set_dead_time (struct rt_device_pwm *device, int channel, rt_uint32_t dead_time)
rt_err_t	rt_pwm_set_phase (struct rt_device_pwm *device, int channel, rt_uint32_t phase)

Detailed Description

PWM driver api.

Example

#include <rtthread.h>
#include <rtdevice.h>
 
#define PWM_DEV_NAME        "pwm3"  // PWM设备名称
#define PWM_DEV_CHANNEL     4       // PWM通道
 
struct rt_device_pwm *pwm_dev;      // PWM设备句柄
 
static int pwm_led_sample(int argc, char *argv[])
{
    rt_uint32_t period, pulse, dir;
 
    period = 500000;    // 周期为0.5ms，单位为纳秒ns
    dir = 1;            // PWM脉冲宽度值的增减方向
    pulse = 0;          // PWM脉冲宽度值，单位为纳秒ns
 
    // 查找设备
    pwm_dev = (struct rt_device_pwm *)rt_device_find(PWM_DEV_NAME);
    if (pwm_dev == RT_NULL)
    {
        rt_kprintf("pwm sample run failed! can't find %s device!\n", PWM_DEV_NAME);
        return -RT_ERROR;
    }
 
    // 设置PWM周期和脉冲宽度默认值
    rt_pwm_set(pwm_dev, PWM_DEV_CHANNEL, period, pulse);
    // 使能设备
    rt_pwm_enable(pwm_dev, PWM_DEV_CHANNEL);
 
    while (1)
    {
        rt_thread_mdelay(50);
        if (dir)
        {
            pulse += 5000;      // 从0值开始每次增加5000ns
        }
        else
        {
            pulse -= 5000;      // 从最大值开始每次减少5000ns
        }
        if (pulse >= period)
        {
            dir = 0;
        }
        if (0 == pulse)
        {
            dir = 1;
        }
 
        // 设置PWM周期和脉冲宽度
        rt_pwm_set(pwm_dev, PWM_DEV_CHANNEL, period, pulse);
    }
}
 
MSH_CMD_EXPORT(pwm_led_sample, pwm sample);

Function Documentation

rt_device_pwm_register()

rt_err_t rt_device_pwm_register	(	struct rt_device_pwm *	device,
		const char *	name,
		const struct rt_pwm_ops *	ops,
		const void *	user_data
	)

register a PWM device

Parameters

device	the PWM device
name	the name of PWM device
ops	the operations of PWM device
user_data	the user data of PWM device

Returns

rt_err_t error code

rt_pwm_enable()

rt_err_t rt_pwm_enable	(	struct rt_device_pwm *	device,
		int	channel
	)

enable the PWM channel

Parameters

device	the PWM device
channel	the channel of PWM

Returns

rt_err_t error code

rt_pwm_disable()

rt_err_t rt_pwm_disable	(	struct rt_device_pwm *	device,
		int	channel
	)

disable the PWM channel

Parameters

device	the PWM device
channel	the channel of PWM

Returns

rt_err_t error code

rt_pwm_set()

rt_err_t rt_pwm_set	(	struct rt_device_pwm *	device,
		int	channel,
		rt_uint32_t	period,
		rt_uint32_t	pulse
	)

set the PWM channel

Parameters

device	the PWM device
channel	the channel of PWM
period	the period of PWM
pulse	the pulse of PWM

Returns

rt_err_t error code

rt_pwm_set_period()

rt_err_t rt_pwm_set_period	(	struct rt_device_pwm *	device,
		int	channel,
		rt_uint32_t	period
	)

set the PWM channel period

Parameters

device	the PWM device
channel	the channel of PWM
period	the period of PWM

Returns

rt_err_t error code

rt_pwm_set_pulse()

rt_err_t rt_pwm_set_pulse	(	struct rt_device_pwm *	device,
		int	channel,
		rt_uint32_t	pulse
	)

set the PWM channel pulse

Parameters

device	the PWM device
channel	the channel of PWM
pulse	the period of PWM

Returns

rt_err_t error code

rt_pwm_set_dead_time()

rt_err_t rt_pwm_set_dead_time	(	struct rt_device_pwm *	device,
		int	channel,
		rt_uint32_t	dead_time
	)

set the dead zone time of PWM

Parameters

device	the PWM device
channel	the channel of PWM
dead_time	dead zone time

Returns

rt_err_t error code

rt_pwm_set_phase()

rt_err_t rt_pwm_set_phase	(	struct rt_device_pwm *	device,
		int	channel,
		rt_uint32_t	phase
	)

set the phase of PWM

Parameters

device	the PWM device
channel	the channel of PWM
phase	phase

Returns

rt_err_t error code