Added basic "Clock" process

Handles setting RTC based on the compile date/time (assuming you'll
compile + upload immediately) and tracking the last time set in eeprom
to avoid resetting every boot

Clock.cpp

@@ -0,0 +1,202 @@
+#include <M5StickC.h>
+#include "Kernel.h"
+#include "EAT.h"
+
+RTC_TimeTypeDef time_to_rtc(char* time);
+RTC_DateTypeDef date_to_rtc(char* date);
+void redraw(RTC_TimeTypeDef time);
+
+int last_minute = -1;
+
+int Clock(int pid, unsigned int signal)
+{
+  if (signal & SIGNAL_START)
+  {
+    Kernel_signal_mask(pid, SIGNAL_START | SIGNAL_STOP | SIGNAL_TICK | SIGNAL_REDRAW);
+    
+    RTC_TimeTypeDef compile_time = time_to_rtc(__TIME__);
+    RTC_DateTypeDef compile_date = date_to_rtc(__DATE__);
+    
+    if (EAT_allocate(2, 6) ||
+        EAT_read(2, 0) != compile_time.Hours ||
+        EAT_read(2, 1) != compile_time.Minutes ||
+        EAT_read(2, 2) != compile_time.Seconds ||
+        EAT_read(2, 3) != (compile_date.Year & 0xFF) ||
+        EAT_read(2, 4) != compile_date.Month ||
+        EAT_read(2, 5) != compile_date.Date)
+    {
+      M5.Rtc.SetTime(&compile_time);
+      M5.Rtc.SetData(&compile_date);  
+
+      EAT_write(2, 0, compile_time.Hours);
+      EAT_write(2, 1, compile_time.Minutes);
+      EAT_write(2, 2, compile_time.Seconds);
+      EAT_write(2, 3, compile_date.Year & 0xFF);
+      EAT_write(2, 4, compile_date.Month);
+      EAT_write(2, 5, compile_date.Date);
+    }
+    Serial.begin(115200);
+    delay(30);
+  }
+  
+  if (signal & SIGNAL_STOP)
+  {
+    return 255;
+  }
+
+  if (signal & SIGNAL_TICK || signal & SIGNAL_REDRAW)
+  {
+    RTC_TimeTypeDef time;
+    M5.Rtc.GetTime(&time);
+
+    if (signal & SIGNAL_TICK) // && time.Minutes != last_minute)
+    {
+      Kernel_signal(SIGNAL_REDRAW);
+    }
+    if (signal & SIGNAL_REDRAW)
+    {
+      Serial.println("Redraw!");
+      redraw(time);
+    }
+  }
+  
+  return 0;
+}
+
+void redraw(RTC_TimeTypeDef time)
+{
+  M5.Lcd.setCursor(0, 40);
+  char time_str[9];
+  sprintf(time_str, "%02d:%02d:%02d", time.Hours, time.Minutes, time.Seconds);
+  M5.Lcd.print(time_str);
+}
+
+RTC_TimeTypeDef time_to_rtc(char* time)
+{
+  RTC_TimeTypeDef time_ret;
+  int buffer_idx = 0;
+  char buffer[3];
+  char* current;
+  int state = 0;
+
+  for (current = time; ; current++)
+  {
+    if (*current == ':' || *current == '\0')
+    {
+      buffer[buffer_idx++] = '\0';
+      int next = atoi(buffer);
+      switch (state++)
+      {
+        case 0:
+          time_ret.Hours = next;
+          break;
+        case 1:
+          time_ret.Minutes = next;
+          break;
+        case 2:
+          time_ret.Seconds = next;
+          break;
+      }
+      buffer_idx = 0;
+    }
+    else
+    {
+      buffer[buffer_idx++] = *current;
+    }
+
+    if (*current == '\0')
+    {
+      break;
+    }
+  }
+
+  return time_ret;
+}
+
+RTC_DateTypeDef date_to_rtc(char* date)
+{
+  RTC_DateTypeDef date_ret;
+  int buffer_idx = 0;
+  char buffer[5];
+  char* current;
+  int state = 0;
+
+  for (current = date; ; current++)
+  {
+    if (*current == ' ' || *current == '\0')
+    {
+      buffer[buffer_idx++] = '\0';
+      switch (state++)
+      {
+        case 0: // month
+          if (strcmp(buffer, "Jan") == 0)
+          {
+            date_ret.Month = 1;
+          }
+          else if (strcmp(buffer, "Feb") == 0)
+          {
+            date_ret.Month = 2;
+          }
+          else if (strcmp(buffer, "Mar") == 0)
+          {
+            date_ret.Month = 3;
+          }
+          else if (strcmp(buffer, "Apr") == 0)
+          {
+            date_ret.Month = 4;
+          }
+          else if (strcmp(buffer, "May") == 0)
+          {
+            date_ret.Month = 5;
+          }
+          else if (strcmp(buffer, "Jun") == 0)
+          {
+            date_ret.Month = 6;
+          }
+          else if (strcmp(buffer, "Jul") == 0)
+          {
+            date_ret.Month = 7;
+          }
+          else if (strcmp(buffer, "Aug") == 0)
+          {
+            date_ret.Month = 8;
+          }
+          else if (strcmp(buffer, "Sep") == 0)
+          {
+            date_ret.Month = 9;
+          }
+          else if (strcmp(buffer, "Oct") == 0)
+          {
+            date_ret.Month = 10;
+          }
+          else if (strcmp(buffer, "Nov") == 0)
+          {
+            date_ret.Month = 11;
+          }
+          else if (strcmp(buffer, "Dec") == 0)
+          {
+            date_ret.Month = 12;
+          }
+          break;
+        case 1: // day
+          date_ret.Date = atoi(buffer);
+          break;
+        case 2: // year
+        date_ret.Year = atoi(buffer);
+          break;
+      }
+      buffer_idx = 0;
+    }
+    else
+    {
+      buffer[buffer_idx++] = *current;
+    }
+    
+    if (*current == '\0')
+    {
+      break;
+    }
+  }
+
+  return date_ret;
+}

Clock.h

@@ -0,0 +1,2 @@
+
+int Clock(int pid, unsigned int signal);