Pololu3piPlus32U4::Encoders Class Reference

Reads counts from the encoders on the 3pi+ 32U4. More...

#include <Pololu3piPlus32U4Encoders.h>

Static Public Member Functions
static void	flipEncoders (bool flip)
	Flips the direction of the encoders. More...
static void	init ()
	Initializes the encoders (called automatically). More...
static int16_t	getCountsLeft ()
	Returns the number of counts that have been detected from the left-side encoder. More...
static int16_t	getCountsRight ()
	Returns the number of counts that have been detected from the right-side encoder. More...
static int16_t	getCountsAndResetLeft ()
	Returns the number of counts that have been detected from the left-side encoder and clears the counts. More...
static int16_t	getCountsAndResetRight ()
	Returns the number of counts that have been detected from the left-side encoder and clears the counts. More...
static bool	checkErrorLeft ()
	Returns true if an error was detected on the left-side encoder. More...
static bool	checkErrorRight ()
	Returns true if an error was detected on the right-side encoder. More...

Detailed Description

Reads counts from the encoders on the 3pi+ 32U4.

This class allows you to read counts from the encoders on the 3pi+ 32U4, which lets you tell how much each motor has turned and in what direction.

The encoders are monitored in the background using interrupts, so your code can perform other tasks without missing encoder counts.

To read the left encoder, this class uses an interrupt service routine (ISR) for PCINT0_vect, so there will be a compile-time conflict with any other code that defines a pin-change ISR.

To read the right encoder, this class calls attachInterrupt(), so there will be a compile-time conflict with any other code that defines an ISR for an external interrupt directly instead of using attachInterrupt().

Definition at line 28 of file Pololu3piPlus32U4Encoders.h.

Member Function Documentation

checkErrorLeft()

bool Pololu3piPlus32U4::Encoders::checkErrorLeft ( )

static

Returns true if an error was detected on the left-side encoder.

This function resets the error flag automatically, so it will only return true if an error was detected since the last time checkErrorLeft() was called.

If an error happens, it means that both of the encoder outputs changed at the same time from the perspective of the ISR, so the ISR was unable to tell what direction the motor was moving, and the encoder count could be inaccurate. The most likely cause for an error is that the interrupt service routine for the encoders could not be started soon enough. If you get encoder errors, make sure you are not disabling interrupts for extended periods of time in your code.

Definition at line 143 of file Pololu3piPlus32U4Encoders.cpp.

checkErrorRight()

bool Pololu3piPlus32U4::Encoders::checkErrorRight ( )

static

Returns true if an error was detected on the right-side encoder.

See also

checkErrorLeft()

Definition at line 152 of file Pololu3piPlus32U4Encoders.cpp.

flipEncoders()

void Pololu3piPlus32U4::Encoders::flipEncoders ( bool  flip )

static

Flips the direction of the encoders.

This is useful if you have to flip the direction of the motors due to a non-standard gearbox.

Parameters

flip	If true, the direction of counting will be reversed relative to the standard 3pi+ 32U4.

Definition at line 96 of file Pololu3piPlus32U4Encoders.cpp.

getCountsAndResetLeft()

int16_t Pololu3piPlus32U4::Encoders::getCountsAndResetLeft ( )

static

Returns the number of counts that have been detected from the left-side encoder and clears the counts.

This function is just like getCountsLeft() except it also clears the counts before returning. If you call this frequently enough, you will not have to worry about the count overflowing.

Definition at line 121 of file Pololu3piPlus32U4Encoders.cpp.

getCountsAndResetRight()

int16_t Pololu3piPlus32U4::Encoders::getCountsAndResetRight ( )

static

Returns the number of counts that have been detected from the left-side encoder and clears the counts.

See also

getCountsAndResetLeft()

Definition at line 132 of file Pololu3piPlus32U4Encoders.cpp.

getCountsLeft()

int16_t Pololu3piPlus32U4::Encoders::getCountsLeft ( )

static

Returns the number of counts that have been detected from the left-side encoder.

The count starts at 0. Positive counts correspond to forward movement of the left side of the 3pi+, while negative counts correspond to backwards movement.

The count is returned as a signed 16-bit integer. When the count goes over 32767, it will overflow down to -32768. When the count goes below -32768, it will overflow up to 32767.

Definition at line 101 of file Pololu3piPlus32U4Encoders.cpp.

getCountsRight()

int16_t Pololu3piPlus32U4::Encoders::getCountsRight ( )

static

Returns the number of counts that have been detected from the right-side encoder.

See also

getCountsLeft()

Definition at line 111 of file Pololu3piPlus32U4Encoders.cpp.

init()

static void Pololu3piPlus32U4::Encoders::init ( )

inlinestatic

Initializes the encoders (called automatically).

This function initializes the encoders if they have not been initialized already and starts listening for counts. This function is called automatically whenever you call any other function in this class, so you should not normally need to call it in your code.

Definition at line 48 of file Pololu3piPlus32U4Encoders.h.

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

• src/Pololu3piPlus32U4Encoders.h
• src/Pololu3piPlus32U4Encoders.cpp