From 913ecf3f3f3099e6901f503c603599399b28289a Mon Sep 17 00:00:00 2001
From: s3lph <s3lph@kabelsalat.ch>
Date: Sun, 7 May 2023 04:58:49 +0200
Subject: [PATCH] fix: proper fallback for datetime display if no NMEA string
 has been received yet

---
 src/main.cpp | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 22a42ba..67429da 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -352,13 +352,18 @@ void printLocation() {
 void printDateTime() {
   char dateTime[17];
   char speedCourse[17];
-  snprintf(dateTime, 17, "%.2s.%.2s.%.2s  %.2s:%.2sz",
-	   rmc.date, rmc.date+2, rmc.date+4,
-	   rmc.time, rmc.time+2);
-  uint16_t kph = (strtol(rmc.speed, NULL, 10) * 463) / 250;
-  uint16_t hdg = strtol(rmc.course, NULL, 10);
-  snprintf(speedCourse, 17, "% 3d km/h% 6d \xdf",
-	   kph, hdg);
+  if (rmc.date[0] != 0) {
+    snprintf(dateTime, 17, "%.2s.%.2s.%.2s  %.2s:%.2sz",
+	     rmc.date, rmc.date+2, rmc.date+4,
+	     rmc.time, rmc.time+2);
+    uint16_t kph = (strtol(rmc.speed, NULL, 10) * 463) / 250;
+    uint16_t hdg = strtol(rmc.course, NULL, 10);
+    snprintf(speedCourse, 17, "% 3d km/h% 6d \xdf",
+	     kph, hdg);
+  } else {
+    snprintf(dateTime, 17, "??.??.??  ??:??z");
+    snprintf(speedCourse, 17, "??? km/h   ??? \xdf");
+  }
   
   lcd.setCursor(0, 0);
   lcd.print(dateTime);
@@ -682,6 +687,7 @@ void setup() {
   attachInterrupt(digitalPinToInterrupt(3), isrAbc, FALLING);
   lcd.init();
   lcd.noDisplay();
+  lcd.noBacklight();
   setPressed = false;
   abcPressed = false;
 }