Classes

The AnalogIn class is used to read the external voltage applied to an analog input pin.

Example: Read and print the analog input value on a analog pin

import SwiftIO

//Initialize an AnalogIn to analog pin A0.
let pin = AnalogIn(Id.A0)

//Read and print the analog input value every 1 second.
while true {
    var value = pin.readVoltage()
    print("The analog input volatge is \(value)")
    sleep(ms: 1000)
}

The counter class can be used to count the external signal and measure the number of the pulse. It can detect the rising edge or both edges.

Example: Read the count value every 10ms

import SwiftIO

// Initiate the counter0.
let counter = Counter(Id.C0)

// Count and print the value every 10ms. Use wait here to get a more precise delay.
while true {
    // Clear the counter to set the value to 0.
    counter.clear()
    wait(us: 10_000)
    // Read the value accumulated in 10ms.
    let value = counter.read()
    print("Conter value = \(value)")
}

or

 import SwiftIO

 // Initiate the counter0.
 let counter = Counter(Id.C0)

 // Initialize a timer to set interrupt.
 let timer = Timer()

 // Use the timer to read and print the value every 10ms.
 timer.setInterrupt(ms: 10) {
     let value = counter.read()
     // Clear the value to to 0.
     counter.clear()
     print("Conter value = \(value)")
 }

 while true {
 }

The DigitalIn class is intended to detect the state of a digital input pin. The input value is either true(1) or false(0).

Example: Read and print the input value on a digital input pin.

import SwiftIO

//Initialize a DigitalIn to the digital pin D0.
let pin = DigitalIn(Id.D0)

//Read and print the input value every 1 second.
while true {
    var value = pin.read()
    print("The input value is \(value)")
    sleep(ms: 1000)
}

The DigitalOut class is used to set a High or Low voltage output to a digital output pin. An initiation is required before using the member functions of this class.

Example: Reverse the output value on a digital output pin

import SwiftIO

// Initiate a DigitalOut to Pin 0.
let pin = DigitalOut(Id.D0)

// Reverse the output value every 1 second.
while true {
    pin.toggle()
    sleep(ms: 1000)
}

or

import SwiftIO

// Initiate a DigitalOut to the onboard green LED.
let greenLED = DigitalOut(Id.GREEN)
​
// Toggle the output of the pin every 1 second using another member function.
while true {
    greenLED.write(true)
    sleep(ms: 1000)
    greenLED.write(false)
    sleep(ms: 1000)
}

I2C (I square C) is a two wire protocol to communicate between different devices. The I2C class allows some operations through I2C protocol, including reading messages from a device and writing messages to a device. Currently the I2C ports support only master mode.

The PWMOut class is used to vary the output voltage by controlling the duration of high output in the time periodCycles on the pin.

Example: Light a LED

import SwiftIO

// Initiate a PWMOut to Pin PWM0A.
let led = PWMOut(Id.PWM0A)

// Set the brightness of the LED by setting the duty cycle.
while true {
    led.setDutycycle(0.5)
}

SPI is a four wire serial protocol for communication between devices.

The Timer class is used to set the occasion to raise the interrupt.

Example: Reverse the output value on a digital output pin

import SwiftIO

let timer = Timer()
let led = DigitalOut(Id.GREEN)

// The setInterrupt function can be written as following:
func toggleLed() {
   led.toggle()
}
timer.setInterrupt(ms: 1000, toggleLed)

while true {
}

or

import SwiftIO

let timer = Timer()
let led = DigitalOut(Id.GREEN)

// Set interrupt with a closure
timer.setInterrupt(ms: 1000) {
   led.toggle()
}

while true {
}

UART is a two-wire serial communication protocol used to communicate with serial devices. The devices must agree on a common transmisson rate before communication.