daisy::GPIO Class Reference

General Purpose I/O control. More...

Detailed Description

General Purpose I/O control.

peripheral control over a single GPIO

Button Input (with internal Pullup resistor)

// GPIO Input
// Example of using a simple button
//
// Setup:
// * Connect one end of a button to GND
// * Connect other end to pin D0 on the Daisy Seed
//
#include "daisy_seed.h"
 
using namespace daisy;
using namespace daisy::seed;
 
DaisySeed hw;
 
int main(void)
{
    // Initialize the Daisy Seed
    hw.Init();
 
    // Start the Serial Logger
    hw.StartLog();
 
    // Create a GPIO object
    GPIO my_button;
 
    // Initialize the GPIO object
    // Mode: INPUT - because we want to read from the button
    // Pullup: Internal resistor to prevent needing extra components
    my_button.Init(D0, GPIO::Mode::INPUT, GPIO::Pull::PULLUP);
 
    while(1)
    {
        // And let's store the state of the button in a variable called "button_state"
        bool button_state = my_button.Read();
 
        // Set the USER LED to the button state
        hw.SetLed(button_state);
 
        // Print the Button state
        hw.PrintLine("Button State: %s", button_state ? "true" : "false");
    }
}

Output Example (perfect for blinking an LED)

// GPIO Output
// Example of toggling an LED on/off
//
// Setup:
// * Connect the CATHODE (negative leg) of the LED to GND
// * Connect the ANODE (positive leg, usually longer) of the LED to one side of a resistor (1K)
// * Connect other end of resistor to pin D1 on the daisy.
//
#include "daisy_seed.h"
 
using namespace daisy;
using namespace daisy::seed;
 
DaisySeed hw;
 
int main(void)
{
    // Initialize the Daisy Seed hardware
    hw.Init();
 
    // Create an LED
    GPIO my_led;
 
    // Initialize it to pin D1 as an OUTPUT
    my_led.Init(D1, GPIO::Mode::OUTPUT);
 
    // In an infinite loop, we'll continuously turn the LED on/off.
    while(1)
    {
        // Set the pin HIGH
        my_led.Write(true);
        // Wait half a second (500ms)
        System::Delay(500);
        // Set the pin LOW
        my_led.Write(false);
        // Wait another half a second (500ms)
        System::Delay(500);
        // You can also use Toggle to change the state
        my_led.Toggle();
        // Wait another half a second (500ms)
        System::Delay(500);
        // And once more to flip it back
        my_led.Toggle();
    }
}

#include <gpio.h>

Classes
struct	Config
	Configuration for a given GPIO. More...

Public Types
enum class	Mode { INPUT , OUTPUT , OPEN_DRAIN , ANALOG }
	Mode of operation for the specified GPIO. More...
enum class	Pull { NOPULL , PULLUP , PULLDOWN }
	Configures whether an internal Pull up or Pull down resistor is used. More...
enum class	Speed { LOW , MEDIUM , HIGH , VERY_HIGH }
	Output speed controls the drive strength, and slew rate of the pin. More...

Public Member Functions
	GPIO ()
void	Init (const Config &cfg)
	Initialize the GPIO from a Config struct.
void	Init (Pin p, const Config &cfg)
	Initialize the GPIO with a Configuration struct, and explicit pin.
void	Init (Pin p, Mode m=Mode::INPUT, Pull pu=Pull::NOPULL, Speed sp=Speed::LOW)
	Explicity initialize all configuration for the GPIO.
void	DeInit ()
	Deinitializes the GPIO pin.
bool	Read ()
	Reads the state of the GPIO.
void	Write (bool state)
	Changes the state of the GPIO hardware when configured as an OUTPUT.
void	Toggle ()
	flips the current state of the GPIO. If it was HIGH, it will go LOW, and vice versa.
Config &	GetConfig ()

Member Enumeration Documentation

Mode

enum class daisy::GPIO::Mode

strong

Mode of operation for the specified GPIO.

Enumerator
INPUT	Input for reading state of pin
OUTPUT	Output w/ push-pull configuration
OPEN_DRAIN	Output w/ open-drain configuration
ANALOG	Analog for connection to ADC or DAC peripheral

Pull

enum class daisy::GPIO::Pull

strong

Configures whether an internal Pull up or Pull down resistor is used.

Internal Pull up/down resistors are typically 40k ohms, and will be between 30k and 50k

When the Pin is configured in Analog mode, the pull up/down resistors are disabled by hardware.

Enumerator
NOPULL	No pull up resistor
PULLUP	Internal pull up enabled
PULLDOWN	Internal pull down enabled

Speed

enum class daisy::GPIO::Speed

strong

Output speed controls the drive strength, and slew rate of the pin.

Enumerator
LOW
MEDIUM
HIGH
VERY_HIGH

Constructor & Destructor Documentation

GPIO()

daisy::GPIO::GPIO ( )

inline

Member Function Documentation

DeInit()

void daisy::GPIO::DeInit

(

)

Deinitializes the GPIO pin.

GetConfig()

Config & daisy::GPIO::GetConfig ( )

inline

Return a reference to the internal Config struct

Init() [1/3]

void daisy::GPIO::Init

(

const Config &

cfg

)

Initialize the GPIO from a Config struct.

Parameters

cfg	reference to a Config struct populated with the desired settings

Init() [2/3]

void daisy::GPIO::Init	(	Pin	p,
		const Config &	cfg
	)

Initialize the GPIO with a Configuration struct, and explicit pin.

Parameters

p	Pin specifying the physical connection on the hardware
cfg	reference to a Config struct populated with the desired settings. Config::pin will be overwritten

Init() [3/3]

void daisy::GPIO::Init	(	Pin	p,
		Mode	m = Mode::INPUT,
		Pull	pu = Pull::NOPULL,
		Speed	sp = Speed::LOW
	)

Explicity initialize all configuration for the GPIO.

Parameters

p	Pin specifying the physical connection on the hardware
m	Mode specifying the behavior of the GPIO (input, output, etc.). Defaults to Mode::INPUT
pu	Pull up/down state for the GPIO. Defaults to Pull::NOPULL
sp	Speed setting for drive strength/slew rate. Defaults to Speed::Slow

Read()

bool daisy::GPIO::Read

(

)

Reads the state of the GPIO.

Returns

State of the GPIO unless Mode is set to Mode::Analog, then always false

Toggle()

void daisy::GPIO::Toggle

(

)

flips the current state of the GPIO. If it was HIGH, it will go LOW, and vice versa.

Write()

void daisy::GPIO::Write

(

bool

state

)

Changes the state of the GPIO hardware when configured as an OUTPUT.

Parameters

state

setting true writes an output HIGH, while setting false writes an output LOW.

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

• src/per/gpio.h