add demo mode

Core/Inc/config.h

@@ -0,0 +1 @@
+// #define DEMO_MODE

Core/Src/vehicle.c

@@ -1,6 +1,7 @@
 #include "vehicle.h"
 
 #include "can-halal.h"
+#include "config.h"
 #include "main.h"
 #include "stm32h7xx.h"
 #include "stm32h7xx_hal.h"
@@ -78,6 +79,17 @@ void vehicle_thread_entry(ULONG hfdcan_addr) {
 
   while (1) {
     tx_thread_sleep(10);
+
+#ifdef DEMO_MODE
+    double tick = HAL_GetTick();
+
+    vehicle_state.speed =
+        (sin(tick * 0.001) * 8 + 10 + cos(tick * 0.003) * 8) * 4;
+    if (vehicle_state.speed <= 0) {
+      vehicle_state.speed = 0;
+    }
+    tx_event_flags_set(&gui_update_events, GUI_UPDATE_VEHICLE_STATE, TX_OR);
+#endif
   }
 }