SetSerial example sketch: Improved error checking on user input when setting time or calibration.

Author: JChristensen

examples/SetSerial/SetSerial.ino

@@ -70,23 +70,41 @@ void setup()
 
 void loop()
 {
-    tmElements_t tm;
-    int cmdChar, y, oldCal, newCal;
+    // check for input, to set rtc time or calibration
+    if (Serial.available()) setRTC();
 
-    // check for input, first character is a command, "S" to set date/time, or "C" to set the calibration register
-    if (Serial.available()) {
-        cmdChar = Serial.read();
+    // print time and date every second
+    static time_t tLast;
+    time_t t { now() };
+    if (t != tLast) {
+        tLast = t;
+        printTime(t);
+    }
+}
+
+void setRTC()
+{
+    // first character is a command, "S" to set date/time, or "C" to set the calibration register
+    int cmdChar = Serial.read();
 
-        switch (cmdChar) {
-            case 'S':
-            case 's':
+    switch (cmdChar) {
+        case 'S':
+        case 's':
+            delay(25);  // wait for all the input to arrive
+            // check for input to set the RTC, minimum length is 13, i.e. yy,m,d,h,m,s<nl>
+            if (Serial.available() < 13) {
+                while (Serial.available()) Serial.read();  // dump extraneous input
+                Serial << F("Input error or timeout, try again.\n");
+            }
+            else {
                 // note that the tmElements_t Year member is an offset from 1970,
                 // but the RTC wants the last two digits of the calendar year.
                 // use the convenience macros from TimeLib.h to do the conversions.
-                y = Serial.parseInt();
+                int y = Serial.parseInt();
                 if (y >= 100 && y < 1000)
-                    Serial << F("Error: Year must be two digits or four digits!") << endl;
+                    Serial << F("Error: Year must be two digits or four digits!\n");
                 else {
+                    tmElements_t tm;
                     if (y >= 1000)
                         tm.Year = CalendarYrToTm(y);
                     else    //(y < 100)
@@ -96,39 +114,43 @@ void loop()
                     tm.Hour = Serial.parseInt();
                     tm.Minute = Serial.parseInt();
                     tm.Second = Serial.parseInt();
-                    time_t t = makeTime(tm);
-                    myRTC.set(t);        // use the time_t value to ensure correct weekday is set
-                    setTime(t);
-                    Serial << F("RTC set to: ");
-                    printTime(t);
-                    Serial << endl;
+                    if (tm.Month == 0 || tm.Day == 0) {
+                        while (Serial.available()) Serial.read();  // dump extraneous input
+                        Serial << F("Input error or timeout, try again.\n");
+                    }
+                    else {
+                        time_t t = makeTime(tm);
+                        myRTC.set(t);        // use the time_t value to ensure correct weekday is set
+                        setTime(t);
+                        Serial << F("RTC set to: ");
+                        printTime(t);
+                    }
                 }
-                break;
+            }
+            break;
 
-            case 'C':
-            case 'c':
-                newCal = Serial.parseInt();
-                oldCal = myRTC.calibRead();
+        case 'C':
+        case 'c':
+            delay(25);  // wait for all the input to arrive
+            if (Serial.available() < 2) {   // minimum valid input at this point is 2 chars
+                while (Serial.available()) Serial.read();  // dump extraneous input
+                Serial << F("Input error or timeout, try again.\n");
+            }
+            else {
+                int newCal = Serial.parseInt();
+                int oldCal = myRTC.calibRead();
                 myRTC.calibWrite(newCal);
                 Serial << F("Calibration changed from ") << oldCal << F(" to ") << myRTC.calibRead() << endl;
-                break;
-
-            default:
-                Serial << endl << F("Unrecognized command: ") << (char)cmdChar << endl;
-                break;
-        }
+            }
+            break;
 
-        // dump any extraneous input
-        while (Serial.available() > 0) Serial.read();
+        default:
+            Serial << endl << F("Unrecognized command: ") << (char)cmdChar << endl;
+            break;
     }
 
-    // print time and date every second
-    static time_t tLast;
-    time_t t { now() };
-    if (t != tLast) {
-        tLast = t;
-        printTime(t);
-    }
+    // dump any extraneous input
+    while (Serial.available()) Serial.read();
 }
 
 // format and print a time_t value