PWM driver

Collaboration diagram for PWM driver:

Functions
void	pwm_init (uint32 period, uint32 *duty, uint32 pwm_channel_num, uint32(*pin_info_list)[3])
	Initialize PWM function, including GPIO selection, period and duty cycle. More...
void	pwm_start (void)
	Starts PWM. More...
void	pwm_set_duty (uint32 duty, uint8 channel)
	Sets duty cycle of a PWM output. More...
uint32	pwm_get_duty (uint8 channel)
	Get duty cycle of PWM output. More...
void	pwm_set_period (uint32 period)
	Set PWM period. More...
uint32	pwm_get_period (void)
	Get PWM period. More...
uint32	get_pwm_version (void)
	Get version information of PWM. More...

Detailed Description

Function Documentation

get_pwm_version()

uint32 get_pwm_version

(

void

)

Get version information of PWM.

Return values

uint32

PWM version

pwm_get_duty()

uint32 pwm_get_duty

(

uint8

channel

)

Get duty cycle of PWM output.

Parameters

channel

PWM channel, which depends on how many PWM channels are used

Return values

uint32

Duty cycle of PWM output

Duty cycle will be (duty*45) / (period*1000).

pwm_get_period()

uint32 pwm_get_period

(

void

)

Get PWM period.

Return values

uint32

Return PWM period in us.

pwm_init()

void pwm_init	(	uint32	period,
		uint32 *	duty,
		uint32	pwm_channel_num,
		uint32(*)	pin_info_list[3]
	)

Initialize PWM function, including GPIO selection, period and duty cycle.

Parameters

period	PWM period
duty	duty cycle of each output
pwm_channel_num	PWM channel number
pin_info_list	Array containing an entry for each channel giving

Note

This API can be called only once.

Example:

    uint32 io_info[][3] = {
        {PWM_0_OUT_IO_MUX, PWM_0_OUT_IO_FUNC, PWM_0_OUT_IO_NUM},
        {PWM_1_OUT_IO_MUX, PWM_1_OUT_IO_FUNC, PWM_1_OUT_IO_NUM},
        {PWM_2_OUT_IO_MUX, PWM_2_OUT_IO_FUNC, PWM_2_OUT_IO_NUM}
};

pwm_init(light_param.pwm_period, light_param.pwm_duty, 3, io_info);

pwm_set_duty()

void pwm_set_duty	(	uint32	duty,
		uint8	channel
	)

Sets duty cycle of a PWM output.

Parameters

duty	The time that high-level single will last, duty cycle will be (duty*45)/(period*1000)
channel	PWM channel, which depends on how many PWM channels are used

Set the time that high-level signal will last. The range of duty depends on PWM period. Its maximum value of which can be Period * 1000 / 45.

For example, for 1-KHz PWM, the duty range is 0 ~ 22222.

pwm_set_period()

void pwm_set_period

(

uint32

period

)

Set PWM period.

Parameters

period

PWM period in us. For example, 1-KHz PWM period = 1000us.

pwm_start()

void pwm_start

(

void

)

Starts PWM.

This function needs to be called after PWM configuration is changed.