otPWM Class Reference
[PWM - Class for PWM management, PWM - Class for PWM management]

Class that stores state and functions for interacting with PCA9685 PWM chip.

#include <otPWM.h>

Inheritance diagram for otPWM:

Public Types
enum	Constants {   SERVOMIN = 150, SERVOMAX = 600, USMIN = 600, USMAX = 2400,   SERVO_FREQ = 50 }
Public Member Functions
	otPWM ()
bool	init (U8 addr=0x40, U8 prescale=0)
bool	reset ()
void	sleep ()
void	wakeup ()
void	setExtClk (U8 prescale)
void	setPWMFreq (float freq)
void	setOutputMode (bool totempole)
U8	getPWM (U8 num)
void	setPWM (U8 num, U16 on, U16 off)
void	setPin (U8 num, U16 val, bool invert=false)
U8	readPrescale (void)
void	writeMicroseconds (U8 num, U16 Microseconds)
void	setTimebase (U32 freq)
U32	getTimebase ()

---

Member Enumeration Documentation

enum otPWM::Constants

Enumeration values: SERVOMIN  This is the 'minimum' pulse length count (out of 4096). SERVOMAX  This is the 'maximum' pulse length count (out of 4096). USMIN  This is the rounded 'minimum' microsecond length based on the minimum pulse of 150. USMAX  This is the rounded 'maximum' microsecond length based on the maximum pulse of 600. SERVO_FREQ  Analog servos run at ~50 Hz updates.

---

Constructor & Destructor Documentation

otPWM.otPWM (   )

Create the class

---

Member Function Documentation

U8 otPWM.getPWM (  U8  num  )

Gets the PWM output of one of the PCA9685 pins Parameters: num  One of the PWM output pins, from 0 to 15 Returns: Requested PWM output value

U32 otPWM.getTimebase (   )

Getter for the internally tracked oscillator used for freq calculations. Returns: The PCA9685 frequency

bool otPWM.init (  U8  addr = 0x40, U8  prescale = 0 )

Init PWM. Call this method as first! Parameters: addr  I2C address, accepted range is 0x40 to 0x7F prescale  Sets External Clock Returns: True on success Reimplemented in otScorpio.

U8 otPWM.readPrescale (  void   )

Reads set Prescale from PCA9685 Returns: prescale value

bool otPWM.reset (   )

Sends a reset command to the PCA9685 chip over I2C

void otPWM.setExtClk (  U8  prescale  )

Sets EXTCLK pin to use the external clock Parameters: prescale  Sets External Clock

void otPWM.setOutputMode (  bool  totempole  )

Sets the output mode of the PCA9685 to either open drain or push pull / totempole. Warning: LEDs with integrated zener diodes should only be driven in open drain mode. Parameters: totempole  Totempole if true, open drain if false.

void otPWM.setPin (  U8  num, U16  val, bool  invert = false )

Helper to set pin PWM output. Sets pin without having to deal with on/off tick placement and properly handles a zero value as completely off and 4095 as completely on. Optional invert parameter supports inverting the pulse for sinking to ground. Parameters: num  One of the PWM output pins, from 0 to 15 val  The number of ticks out of 4096 to be active, should be a value from 0 to 4095 inclusive. invert  If true, inverts the output, defaults to 'false'

void otPWM.setPWM (  U8  num, U16  on, U16  off )

Sets the PWM output of one of the PCA9685 pins Parameters: num  One of the PWM output pins, from 0 to 15 on  At what point in the 4096-part cycle to turn the PWM output ON off  At what point in the 4096-part cycle to turn the PWM output OFF

void otPWM.setPWMFreq (  float  freq  )

Sets the PWM frequency for the entire chip, up to ~1.6 KHz Parameters: freq  Floating point frequency that we will attempt to match

void otPWM.setTimebase (  U32  freq  )

Setter for the internally tracked oscillator used for freq calculations Parameters: freq  The frequency the PCA9685 should use for frequency calculations

void otPWM.sleep (   )

Puts PWM into sleep mode

void otPWM.wakeup (   )

Wakes PWM from sleep

void otPWM.writeMicroseconds (  U8  num, U16  Microseconds )

Sets the PWM output of one of the PCA9685 pins based on the input microseconds, output is not precise Parameters: num  One of the PWM output pins, from 0 to 15 Microseconds  The number of Microseconds to turn the PWM output ON

---

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

• otPWM.h

otStudio - Library Reference - (C) 2020-23 Officina Turini, All Rights Reserved
Document built with Doxygen 1.4.0