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daisy::GPIO

Module: LIBDAISY / PERIPHERAL

General Purpose I/O control. More...

#include <gpio.h>

Public Classes

Name
struct Config
Configuration for a given GPIO.

Public Types

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

Public Functions

Name
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()

Detailed Description

class daisy::GPIO;

General Purpose I/O control.

peripheral control over a single GPIO

Button Input (with internal Pullup resistor) ```cpp

// 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");
}

} _Filename: GPIO_Input.cpp_ Output Example (perfect for blinking an LED)cpp // 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(); } } ```

Filename: GPIO_Output.cpp

Public Types Documentation

enum Mode

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

Mode of operation for the specified GPIO.

enum Pull

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

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.

enum Speed

Enumerator Value Description
LOW
MEDIUM
HIGH
VERY_HIGH

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

Public Functions Documentation

function GPIO

inline GPIO()

function Init

void Init(
    const Config & cfg
)

Initialize the GPIO from a Config struct.

Parameters:

  • cfg reference to a Config struct populated with the desired settings

function Init

void 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

function Init

void 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

function DeInit

void DeInit()

Deinitializes the GPIO pin.

function Read

bool Read()

Reads the state of the GPIO.

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

function Write

void 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.

function Toggle

void Toggle()

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

function GetConfig

inline Config & GetConfig()

Return a reference to the internal Config struct

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Updated on 2024-01-03 at 19:41:01 +0000