Implement simple fan control

Core/Inc/FanControl.h

@@ -5,8 +5,14 @@
 #include "stm32f4xx_hal_def.h"
 #include "stm32f4xx_hal_tim.h"
 
+typedef enum { FANS_OFF, FANS_ON } FanState;
+
+extern FanState fan_state;
+
 HAL_StatusTypeDef fan_ctrl_init(TIM_HandleTypeDef* handle, uint32_t channel);
 
+void fan_ctrl_update();
+
 /**
  * @brief Set the power of the fan (0 -> off, 100 -> full power).
  */

Core/Inc/main.h

@@ -59,6 +59,10 @@ extern uint8_t slave_id;
 #define THRESH_OV 55050        /* 4.2V */
 #define THRESH_UT 0            /* 0C */
 #define THRESH_OT 880          /* 55C */
+
+#define THRESH_FANS_ON_HALF 640 /* 40C */
+#define THRESH_FANS_ON_FULL 800 /* 50C */
+#define THRESH_FANS_OFF 560     /* 35C */
 /* USER CODE END EM */
 
 void HAL_TIM_MspPostInit(TIM_HandleTypeDef* htim);