Added software timers

Accessory state machine framework functional

source/soft_timer.h

@@ -0,0 +1,36 @@
+#ifndef SOFT_TIMER_H
+#define SOFT_TIMER_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#define MAX_TIMERS 8
+
+typedef enum {
+    TIMER_MODE_ONE_SHOT,
+    TIMER_MODE_PERIODIC
+} timer_mode_t;
+
+typedef void (*timer_callback_t)(void* context);
+
+typedef struct {
+    uint32_t timeout_ticks;
+    uint32_t remaining_ticks;
+    bool active;
+    bool inUse;
+    bool fired;
+    timer_mode_t mode;
+    timer_callback_t callback;
+    void* callback_context;
+} soft_timer_t;
+
+void stimer_init(void);
+int stimer_start(uint32_t timeout_ticks, timer_mode_t mode, timer_callback_t cb, void* ctx);
+void stimer_stop(int timer_id);
+void stimer_end(int timer_id);
+bool stimer_fired(int timer_id);
+bool stimer_clearFired(int timer_id);
+void stimer_update(void);  // Should be called from timer ISR
+bool stimer_is_active(int timer_id);
+
+#endif