See Quickstart guide for AVR XMEGA PWM service.

This is a service for single slope wave form generation on the XMEGA. It provides functions for enabling, disabling and configuring the TC modules in single slope PWM mode.

The API uses a structure which contain the configuration. This structure must be set up before the PWM can be started.

Dependencies

This driver depends on the following modules:

Timer Counter (TC) to set up TC in PWM mode.

Modules
	Related Project(s)
	In this section you can find all the projects related to the XMEGA Pulse Width Modulation (PWM) service.

	Quick Start Guide(s)
	In this section you can find a list of all Quick Start guides related to the XMEGA Pulse Width Modulation (PWM) service.

Data Structures
struct	pwm_config
	PWM configuration. More...

Typedefs
typedef void(*	pwm_callback_t )(void)
	Interrupt callback type. More...

Enumerations
enum	pwm_channel_t { PWM_CH_A = 1, PWM_CH_B = 2, PWM_CH_C = 3, PWM_CH_D = 4 }
	PWM compare channel index. More...

enum	pwm_clk_sel { PWM_CLK_OFF = TC_CLKSEL_OFF_gc, PWM_CLK_DIV1 = TC_CLKSEL_DIV1_gc, PWM_CLK_DIV2 = TC_CLKSEL_DIV2_gc, PWM_CLK_DIV4 = TC_CLKSEL_DIV4_gc, PWM_CLK_DIV8 = TC_CLKSEL_DIV8_gc, PWM_CLK_DIV64 = TC_CLKSEL_DIV64_gc, PWM_CLK_DIV256 = TC_CLKSEL_DIV256_gc, PWM_CLK_DIV1024 = TC_CLKSEL_DIV1024_gc }
	Valid clock source indexes. More...

enum	pwm_tc_t { PWM_TCC0, PWM_TCC1, PWM_TCD0, PWM_TCD1, PWM_TCE0, PWM_TCE1, PWM_TCF0, PWM_TCF1 }
	Valid timer/counters to use. More...

Functions
static void	pwm_disable (struct pwm_config *config)
	Disable the PWM timer. More...

void	pwm_init (struct pwm_config *config, enum pwm_tc_t tc, enum pwm_channel_t channel, uint16_t freq_hz)
	Initialize PWM configuration struct and set correct I/O pin to output. More...

static void	pwm_overflow_int_callback (struct pwm_config *config, pwm_callback_t callback)
	Callback function for timer overflow interrupts. More...

static void	pwm_set_duty_cycle_percent (struct pwm_config *config, uint8_t duty_cycle_scale)
	Function to set PWM duty cycle. More...

void	pwm_set_frequency (struct pwm_config *config, uint16_t freq_hz)
	Calculate TC settings from PWM frequency. More...

void	pwm_start (struct pwm_config *config, uint8_t duty_cycle_scale)
	Start a PWM channel. More...

static void	pwm_stop (struct pwm_config *config)
	Function that stops the PWM timer. More...

static void	pwm_timer_reset (struct pwm_config *config)
	Function that resets the PWM timer. More...

typedef void(* pwm_callback_t)(void)

Interrupt callback type.

enum pwm_channel_t

PWM compare channel index.

Enumerator
PWM_CH_A	Channel A. PWM output on pin 0
PWM_CH_B	Channel B. PWM output on pin 1
PWM_CH_C	Channel C. PWM output on pin 2
PWM_CH_D	Channel D. PWM output on pin 3

enum pwm_clk_sel

Valid clock source indexes.

Enumerator
PWM_CLK_OFF
PWM_CLK_DIV1
PWM_CLK_DIV2
PWM_CLK_DIV4
PWM_CLK_DIV8
PWM_CLK_DIV64
PWM_CLK_DIV256
PWM_CLK_DIV1024

enum pwm_tc_t

Valid timer/counters to use.

Note: Not all timer/counters are available on all devices. Please refer to the datasheet for more information on what timer/counters are available for the device you are using.

Enumerator
PWM_TCC0	PWM on port C, pin 0, 1, 2 or 3 (depending on channel)
PWM_TCC1	PWM on port C, pin 4 or 5 (depending on channel)
PWM_TCD0	PWM on port D, pin 0, 1, 2 or 3 (depending on channel)
PWM_TCD1	PWM on port D, pin 4 or 5 (depending on channel)
PWM_TCE0	PWM on port E, pin 0, 1, 2 or 3 (depending on channel)
PWM_TCE1	PWM on port E, pin 4 or 5 (depending on channel)
PWM_TCF0	PWM on port F, pin 0, 1, 2 or 3 (depending on channel)
PWM_TCF1	PWM on port F, pin 4 or 5 (depending on channel)

static void pwm_disable ( struct pwm_config * config )

inlinestatic

Disable the PWM timer.

This function disables the peripheral clock for the timer and shut down module when unused in order to save power.

Parameters

*config Pointer to the PWM configuration struct

References pwm_stop(), pwm_config::tc, and tc_disable().

void pwm_init	(	struct pwm_config *	config,
		enum pwm_tc_t	tc,
		enum pwm_channel_t	channel,
		uint16_t	freq_hz
	)

Initialize PWM configuration struct and set correct I/O pin to output.

Parameters

config	Pointer to PWM configuration struct.
tc	TC to use for this PWM.
channel	CC channel to use for this PWM.
freq_hz	Frequency to use for this PWM.

References Assert, pwm_config::cc_mask, pwm_config::channel, pwm_config::clk_sel, pwm_config::period, PWM_CH_A, PWM_CH_B, PWM_CH_C, PWM_CH_D, PWM_CLK_OFF, pwm_set_frequency(), PWM_TCC0, PWM_TCC1, PWM_TCD0, PWM_TCD1, PWM_TCE0, PWM_TCE1, PWM_TCF0, PWM_TCF1, pwm_config::tc, TC_CCAEN, TC_CCBEN, TC_CCCEN, TC_CCDEN, tc_enable(), tc_set_wgm(), TC_WG_SS, tc_write_clock_source(), and UNUSED.

Referenced by main().

static void pwm_overflow_int_callback	(	struct pwm_config *	config,
		pwm_callback_t	callback
	)

inlinestatic

Callback function for timer overflow interrupts.

This function enables T/C overflow interrupts (low level interrupts) and defines the callback function for the overflow ISR interrupt routine.

Parameters

*config	Pointer to the PWM configuration struct
callback	Callback function

References pwm_config::tc, TC_INT_LVL_LO, tc_set_overflow_interrupt_callback(), and tc_set_overflow_interrupt_level().

Referenced by main().

static void pwm_set_duty_cycle_percent	(	struct pwm_config *	config,
		uint8_t	duty_cycle_scale
	)

inlinestatic

Function to set PWM duty cycle.

The duty cycle can be set on a scale between 0-100%. This value will be used to update the CCx register for the selected PWM channel.

Parameters

*config	Pointer to the PWM configuration struct
duty_cycle_scale	Duty cycle as a value between 0 and 100.

References Assert, pwm_config::channel, pwm_config::period, pwm_config::tc, and tc_write_cc_buffer().

Referenced by pwm_callback_1(), pwm_callback_2(), and pwm_start().

void pwm_set_frequency	(	struct pwm_config *	config,
		uint16_t	freq_hz
	)

Calculate TC settings from PWM frequency.

This function will find the correct TC settings (clock prescaler and period) which will give the wanted PWM frequency.

Note: Since we want to be able to run the PWM at all duty-cycles ranging from 0-100%, we require a period of at least 100 to achieve this. Thus, the highest possible PWM frequency is CPU frequency / 100.

Parameters

config	Pointer to PWM configuration.
freq_hz	Wanted PWM frequency in Hz.

References Assert, pwm_config::clk_sel, pwm_config::period, PWM_CLK_DIV1, PWM_CLK_DIV1024, PWM_CLK_DIV2, PWM_CLK_DIV256, PWM_CLK_DIV4, PWM_CLK_DIV64, PWM_CLK_DIV8, PWM_CLK_OFF, and sysclk_get_cpu_hz().

Referenced by pwm_init().

void pwm_start	(	struct pwm_config *	config,
		uint8_t	duty_cycle_scale
	)

Start a PWM channel.

This function enables a channel with a given duty cycle.

Parameters

*config	Pointer to the PWM configuration struct
duty_cycle_scale	Duty cycle as a value between 0 and 100.

References pwm_config::cc_mask, pwm_config::clk_sel, pwm_config::period, pwm_set_duty_cycle_percent(), pwm_config::tc, tc_enable_cc_channels(), tc_write_clock_source(), and tc_write_period().

Referenced by main().

static void pwm_stop ( struct pwm_config * config )

inlinestatic

Function that stops the PWM timer.

The PWM timer is stopped by writing the prescaler register to "clock off"

Parameters

*config Pointer to the PWM configuration struct

References pwm_config::tc, and tc_write_clock_source().

Referenced by pwm_disable().

static void pwm_timer_reset ( struct pwm_config * config )

inlinestatic

Function that resets the PWM timer.

This function reset the CNT register for the selected timer used for PWM

Parameters

*config Pointer to the PWM configuration struct

References pwm_config::tc, and tc_write_count().

Microchip® Advanced Software Framework

Dependencies

Modules

Data Structures

Typedefs

Enumerations

Functions