show uptime

1 files changed, 38 insertions, 1 deletions

diff --git a/display.h b/display.h
index 5c9a4a9..a07c86d 100644
--- a/display.h
+++ b/display.h
@@ -11,15 +11,48 @@
 
 #include "data.h"
 
+class TimeStr {
+private:
+  char str[10];
+
+  unsigned long cut(unsigned long &val, unsigned long max) {
+    unsigned long ret = val/max;
+    val %= max;
+    return ret;
+  }
+public:
+  TimeStr() :str("000:00:00") {}
+
+  const char *format(unsigned long now_millis) {
+    unsigned long now_s = now_millis/1000;
+    unsigned long now_m = cut(now_s,60);
+    unsigned long now_h = cut(now_m,60);
+
+    str[0]='0' + cut(now_h,100);
+    str[1]='0' + cut(now_h,10);
+    str[2]='0' + now_h;
+
+    str[4]='0' + cut(now_m,10);
+    str[5]='0' + now_m;
+
+    str[7]='0' + cut(now_s,10);
+    str[8]='0' + now_s;
+
+    return &str[0];
+  }
+};
+
 class Display {
 private:
   GxIO_Class io;
   GxEPD_Class display;
+  TimeStr timeStr;
 
 public:
   Display() :
     io(SPI, EPD_CS, EPD_DC, EPD_RSET),
-    display(io, EPD_RSET, EPD_BUSY)
+    display(io, EPD_RSET, EPD_BUSY),
+    timeStr()
   {}
 
   void start() {
@@ -59,6 +92,10 @@ public:
     display.setCursor(120,30);
     display.print("Batt "); display.print(data->batteryVoltage);
 
+    display.setCursor(0,120);
+    display.print("Uptime ");
+    display.print(timeStr.format(millis()));
+
     // "partial" update
     display.updateWindow(0, 0, GxEPD_WIDTH, GxEPD_HEIGHT, false);