nRF52 PWM driver

Collaboration diagram for nRF52 PWM driver:

Data Structures
struct	pwm_state_t
struct	pwm_channel_config_t
struct	pwm_t

Macros
#define	PWM_NUM_CHANNELS   4

Functions called from application programs
void	PwmInit (const struct pwm_t *Pwm)
	Name: PwmInit Initialize PWM. More...
void	PwmSet (const struct pwm_t *Pwm, uint8_t Channel, uint16_t Value)
	Name: PwmSet Sets PWM duty cycle for the selected channel. More...
void	PwmFrequencySet (const struct pwm_t *Pwm, uint32_t Frequency)
	Name: PwmFrequencySet Sets the PWM frequency. This frequency will be used for all channels on the selected timer. More...
void	PwmInterruptHandler (const struct pwm_t *Pwm)
	Name: PwmInterruptHandler PWM interrupt handler Called from board.c at hardware interrupt context. More...

Detailed Description

This PWM driver can be used for PWM0, PWM1 and PWM2. For each PWM instance, state variables must be initilalized in RAM, and configuration data must be initilalized in FLASH.

The state variable is of type struct pwm_state_t, and is used to hold a copy of used PWM values. The variable should not be initialized.

The configuration data is of type struct pwm_t, and is used to set:

• Which PWM block to be used
• Clock prescaler
• A pointer to the PWM state
• Frequency: The frequency in Hz for the generated PWM
• Mode: Edge- or center-aligned pulse generation
• Range: The range for the PWM (counts from 0 to Range) Example: 100: Result in % resolution (0 to 100) 1023: 10 bits resolution (0 to 1023)
• Which channels to be used and which channels with inverted outputs (struct pwm_channel_config_t)
• Location: Selects location for the PWM output pins (_TIMER_ROUTE_LOCATION_LOC0 – 6)

The timer is counting from 0 to TOP value. TOP value = (16 MHz clock / (2^Prescaler) / Frequency). Care must be taken to obtain enough resolution. Set Prescaler as low as possible.

Macro Definition Documentation

#define PWM_NUM_CHANNELS   4

Number of PWM channels available

Definition at line 81 of file pwm.h.

Function Documentation

void PwmInit

(

const struct pwm_t *

Pwm

)

Name: PwmInit
Initialize PWM.

Parameters

Pwm	Configuration structure for PWM to be used.

void PwmSet	(	const struct pwm_t *	Pwm,
		uint8_t	Channel,
		uint16_t	Value
	)

Name: PwmSet
Sets PWM duty cycle for the selected channel.

Parameters

Pwm	Configuration structure for PWM to be used.
Channel	0-2
Value	PWM active time (0 to Range set in struct pwm_t)

void PwmFrequencySet	(	const struct pwm_t *	Pwm,
		uint32_t	Frequency
	)

Name: PwmFrequencySet
Sets the PWM frequency. This frequency will be used for all channels on the selected timer.

Parameters

Pwm	Configuration structure for PWM to be used.
Frequency	The frequency in Hz for the generated PWM

void PwmInterruptHandler

(

const struct pwm_t *

Pwm

)

Name: PwmInterruptHandler
PWM interrupt handler Called from board.c at hardware interrupt context.

Parameters

Pwm	PWM instance