Embedded compatiable

Signed-off-by: Andy Liu <andy@madmachine.io>

Examples/SwiftIOPlayground/03Buzzer/ReflexGame/Sources/main.swift

@@ -34,10 +34,12 @@ while true {
         }
 
         // Calculate the time in ns.
-        let duration = cyclesToNanoseconds(start: startClockCycle, stop: getClockCycle())
+        let ns = cyclesToNanoseconds(start: startClockCycle, stop: getClockCycle())
+        let duration = ns / 1000_000
+
         // Turn off the indicator.
         led.low()
-        print("Reflex time: \(Float(duration) / 1000_000)ms")
+        print("Reflex time: \(duration)ms")
     }
 
     sleep(ms: 10)

Examples/SwiftIOPlayground/05Humiture/AverageTemperature/Sources/main.swift

@@ -35,13 +35,22 @@ while true {
             sum += humiture.readCelsius()
             sleep(ms: 3)
         }
+        let temperature = sum / 20.0
+        let string = getFloatString(temperature)
 
         // Print the average temperature in celsius.
-        print("Temperature: \(sum / 20.0)C")
+        print("Temperature: " + string + "C")
         startMeasurement = false
         // Turn off the indicator.
         led.low()
     }
 
     sleep(ms: 20)
+}
+
+
+func getFloatString(_ num: Float) -> String {
+    let int = Int(num)
+    let frac = Int((num - Float(int)) * 100)
+    return "\(int).\(frac)"
 }

Examples/SwiftIOPlayground/05Humiture/Humiture/Sources/main.swift

@@ -14,7 +14,16 @@ let humiture = SHT3x(i2c)
 while true {
     let temp = humiture.readCelsius()
     let humidity = humiture.readHumidity()
-    print("Temperature: \(temp)C")
-    print("Humidity: \(humidity)%")
+    let tempStr = getFloatString(temp)
+    let humidityStr = getFloatString(humidity)
+
+    print("Temperature: " + tempStr + "C")
+    print("Humidity: " + humidityStr + "%")
     sleep(ms: 1000)
+}
+
+func getFloatString(_ num: Float) -> String {
+    let int = Int(num)
+    let frac = Int((num - Float(int)) * 100)
+    return "\(int).\(frac)"
 }

Examples/SwiftIOPlayground/06RTC/Alarm/Sources/main.swift

@@ -15,12 +15,19 @@ let buzzer = PWMOut(Id.PWM5A)
 // Stop the alarm after it goes off.
 let stopButton = DigitalIn(Id.D1)
 
+let daysOfWeek = [
+    "Monday", "Tuesday", "Wednesday",
+    "Thursday", "Friday", "Saturday",
+    "Sunday"
+]
+
 // Set the alarm time.
 let alarm = AlarmTime(hour: 10, minute: 40)
 // Calculate the time when the alarm will stop sounding.
 let stopAlarm = getStopAlarm(alarm, after: 1)
 var isAlarmed = false
 
+
 while true {
     let time = rtc.readTime()
 
@@ -29,15 +36,15 @@ while true {
         // if it's time to stop sounding or you press the stop button,
         // stop the sound and turn off the LED.
         if stopAlarm.isTimeUp(time) || stopButton.read() {
-            print("Current time: \(time)")
+            print("Current time: " + formatDateTime(time))
             led.low()
             buzzer.suspend()
             isAlarmed = false
         }
     } else {
         // If the time comes, start the sound and turn on the LED.
         if alarm.isTimeUp(time) {
-            print("Current time: \(time)")
+            print("Current time: " + formatDateTime(time))
             led.high()
             buzzer.set(frequency: 500, dutycycle: 0.5)
             isAlarmed = true
@@ -47,6 +54,21 @@ while true {
     sleep(ms: 10)
 }
 
+// Add leading zero if number is one-digit.
+// For example, number 1 will be 01.
+func formatNum(_ number: UInt8) -> String {
+    return number < 10 ? "0\(number)" : "\(number)"
+}
+
+// Format the date and time, i.e. 2023/03/01 Wednesday 16:20:00.
+func formatDateTime(_ time: PCF8563.Time) -> String {
+    var string = ""
+    string += "\(time.year)" + "/" + formatNum(time.month) + "/" + formatNum(time.day)
+    string += " " + daysOfWeek[Int(time.dayOfWeek)] + " "
+    string += formatNum(time.hour) + ":" + formatNum(time.minute) + ":" + formatNum(time.second)
+    return string
+}
+
 // Calculate the time for alarm to stop sounding after specified minutes.
 func getStopAlarm(_ alarm: AlarmTime, after min: Int) -> AlarmTime {
     var stopMinute = alarm.minute + min

Examples/SwiftIOPlayground/07Accelerometer/Accelerometer/Sources/main.swift

@@ -12,9 +12,21 @@ let accelerometer = LIS3DH(i2c)
 // Read the accelerations and each of them.
 while true {
     let accelerations = accelerometer.readXYZ()
-    print("x: \(accelerations.x)g")
-    print("y: \(accelerations.y)g")
-    print("z: \(accelerations.z)g")
+    let xValue = getFloatString(accelerations.x) + "g"
+    let yValue = getFloatString(accelerations.y) + "g"
+    let zValue = getFloatString(accelerations.z) + "g"
+
+    print("x: " + xValue)
+    print("y: " + yValue)
+    print("z: " + zValue)
     print("\n")
+
     sleep(ms: 1000)
+}
+
+
+func getFloatString(_ num: Float) -> String {
+    let int = Int(num)
+    let frac = Int((num - Float(int)) * 100)
+    return "\(int).\(frac)"
 }

Examples/SwiftIOPlayground/07Accelerometer/AccelerometerLock/Sources/main.swift

@@ -42,6 +42,7 @@ timer.setInterrupt(start: false) {
     reset = true
 }
 
+sleep(ms: 1000)
 print("Tilt/move your board to start.")
 
 while true {

Examples/SwiftIOPlayground/10UART/RemoteLEDSwitch/LED/Sources/main.swift

@@ -7,7 +7,7 @@ import MadBoard
 
 
 let uart = UART(Id.UART0)
-let led = DigitalOut(Id.BLUE)
+let led = DigitalOut(Id.BLUE, value: true)
 
 var buffer: [UInt8] = []
 
@@ -22,18 +22,22 @@ while true {
 
     // Match the message and change the LED state.
     if buffer.count > 0 {
+        // Add a null symbol at the end.
+        buffer.append(0)
+
         // The message from another board is sent in cString 
         // which means the last data is 0, so you need to convert
         // the data in buffer to string using the given encoding. 
         let command = String(cString: buffer)
+        print("Received command: " + command)
 
         buffer.removeAll()
 
         switch command {
         case "on": 
-            led.high()
-        case "off": 
             led.low()
+        case "off": 
+            led.high()
         default: break
         }
     }

Examples/SwiftIOPlayground/12FileSystem/WritingCSVFile/Sources/WritingCSVFile.swift

@@ -9,15 +9,9 @@ public struct WritingCSVFile {
         let i2c = I2C(Id.I2C0)
         let humiture = SHT3x(i2c)
         let rtc = PCF8563(i2c)
+        let led = DigitalOut(Id.D18, value: true)
 
-        // Update the RTC time if it is not current.
-        let currentTime = PCF8563.Time(
-            year: 2024, month: 6, day: 3, hour: 15,
-            minute: 0, second: 0, dayOfWeek: 0
-        )
-        rtc.setTime(currentTime)
-
-        var written = false
+        sleep(ms: 500)
 
         do {
             // Create a csv file on SD card.
@@ -29,11 +23,22 @@ public struct WritingCSVFile {
             print(error)
         }
 
+        // Update the RTC time if it is not current.
+        let currentTime = PCF8563.Time(
+            year: 2024, month: 6, day: 3, hour: 15,
+            minute: 0, second: 0, dayOfWeek: 0
+        )
+        let startMinute = currentTime.minute
+        var previousSecond = currentTime.second
+
+        rtc.setTime(currentTime)
+
         while true {
             let time = rtc.readTime()
 
-            // Read and store the temperature at the start of every minute.
-            if time.second == 0 && !written {
+            // Read and store the temperature every second for a duration of 1 minute.
+            if time.second != previousSecond && time.minute == startMinute {
+                previousSecond = time.second
                 do {
                     let file = try FileDescriptor.open("/SD:/temperature.csv")
                     // Move file offset to the end in order to store new values.
@@ -53,14 +58,14 @@ public struct WritingCSVFile {
 
                     try file.close() 
                 } catch {
+                    led.low()
                     print(error)
                 }
-                written = true
-            } else if time.second == 59 && written {
-                written = false
+            } else if time.minute != startMinute {
+                led.low()
             }
 
-            sleep(ms: 10)
+            sleep(ms: 50)
         }
 
         func formatNum(_ number: UInt8) -> String {