DS3231 Alarm features (#805)

* Added alarm features
* more functions
* chore: fix typo
* feat(ds3231): add Alarm2Mode type and mode consts
* docs(ds3231): add docstrings for SQW functions
* feat(ds3231): add methods for Alarm2
* fix(ds3231): use Alarm2Mode for SetAlarm2 method
* docs(ds3231): add example for alarms
* docs(ds3231): refactor alarms example
* make main function more concise to avoid llvm error for pico
* ci(ds3231): split basic and alarm tests
* style(ds3231): reorder private funcs to the bottom
* docs(ds3231): add docstring for alarm modes
* docs(ds3231): make alarm docstrings more descriptive
* chore(ds3231): fix typo in docstring
* style(ds3231): reorder public functions
* style(ds3231): reorder private methods
* chore(ds3231): add missing error handling
* feat(ds3231): use setter funcs for en/disabling instead of separate funcs
* fix(ds3231): correctly enable alarms in example
* style(ds3231): rename SetEnable32K to SetEnabled32K for consistency
* refactor(ds3231): replace legacy with regmap package
* refactor(ds3231): use Write32 instead of Tx for SetAlarm1
* chore(ds3231): remove fmt deps and and use println in examples
* refactor(ds3231): read temperature as uint16

---------

Co-authored-by: Matthias Fulz <mfulz@olznet.de>

examples/ds3231/alarms/main.go

@@ -0,0 +1,74 @@
+// Connects to an DS3231 I2C Real Time Clock (RTC) and sets both alarms. It then repeatedly checks
+// if the alarms are firing and prints out a message if that is the case.
+package main
+
+import (
+	"machine"
+	"time"
+
+	"tinygo.org/x/drivers/ds3231"
+)
+
+func main() {
+	machine.I2C0.Configure(machine.I2CConfig{})
+
+	rtc := ds3231.New(machine.I2C0)
+	rtc.Configure()
+
+	valid := rtc.IsTimeValid()
+	if !valid {
+		date := time.Date(2019, 12, 05, 20, 34, 12, 0, time.UTC)
+		rtc.SetTime(date)
+	}
+
+	// Set alarm1 so it triggers when the seconds match 59 => repeats every minute at dd:hh:mm:59
+	if err := rtc.SetAlarm1(time.Date(0, 0, 0, 0, 0, 59, 0, time.UTC), ds3231.A1_SECOND); err != nil {
+		println("Error while setting Alarm1")
+	}
+	if err := rtc.SetEnabledAlarm1(true); err != nil {
+		println("Error while enabling Alarm1")
+	}
+
+	// Set alarm2 so it triggers when the minutes match 35 => repeats every hour at dd:hh:35:ss
+	if err := rtc.SetAlarm2(time.Date(0, 0, 0, 0, 35, 0, 0, time.UTC), ds3231.A2_MINUTE); err != nil {
+		println("Error while setting Alarm2")
+	}
+	if err := rtc.SetEnabledAlarm2(true); err != nil {
+		println("Error while enabling Alarm2")
+	}
+
+	running := rtc.IsRunning()
+	if !running {
+		err := rtc.SetRunning(true)
+		if err != nil {
+			println("Error configuring RTC")
+		}
+	}
+
+	for {
+		dt, err := rtc.ReadTime()
+		if err != nil {
+			println("Error reading date:", err)
+			continue
+		}
+
+		a1 := rtc.IsAlarm1Fired()
+		a2 := rtc.IsAlarm2Fired()
+
+		println(dt.Format(time.DateTime), "A1:", a1, "A2:", a2)
+
+		if a1 {
+			if err := rtc.ClearAlarm1(); err != nil {
+				println("Error while clearing alarm1")
+			}
+		}
+		if a2 {
+			if err := rtc.ClearAlarm2(); err != nil {
+				println("Error while clearing alarm2")
+			}
+
+		}
+
+		time.Sleep(time.Second * 1)
+	}
+}

examples/ds3231/basic/main.go

@@ -3,10 +3,9 @@ package main
 
 import (
 	"machine"
+	"strconv"
 	"time"
 
-	"fmt"
-
 	"tinygo.org/x/drivers/ds3231"
 )
 
@@ -26,19 +25,19 @@ func main() {
 	if !running {
 		err := rtc.SetRunning(true)
 		if err != nil {
-			fmt.Println("Error configuring RTC")
+			println("Error configuring RTC")
 		}
 	}
 
 	for {
 		dt, err := rtc.ReadTime()
 		if err != nil {
-			fmt.Println("Error reading date:", err)
+			println("Error reading date:", err)
 		} else {
-			fmt.Printf("Date: %d/%s/%02d %02d:%02d:%02d \r\n", dt.Year(), dt.Month(), dt.Day(), dt.Hour(), dt.Minute(), dt.Second())
+			println(dt.Format(time.DateTime))
 		}
 		temp, _ := rtc.ReadTemperature()
-		fmt.Printf("Temperature: %.2f °C \r\n", float32(temp)/1000)
+		println("Temperature:", strconv.FormatFloat(float64(temp)/1000, 'f', -1, 32), "°C")
 
 		time.Sleep(time.Second * 1)
 	}