pwm uart gipo i2c

3rd/lowpass_filter.c

@@ -0,0 +1,42 @@
+
+#include <stdint.h>
+
+
+float y = 0;
+float Lowpassfilter_sim(float x)
+{
+	float out = 0.9*x + 0.1*y;
+	y = x;
+	return out;
+}
+
+uint32_t Last_Timesamp = 0.0;
+float Last_y = 0.0;
+float Lowpassfilter(float Tf, float x)
+{
+	float dt = 0.0;
+
+	//TODO
+	uint32_t Timesamp = 0;
+	//uint32_t Timestamp = SysTick->VAL;
+	if(Timesamp < Last_Timesamp) dt = (float)(Last_Timesamp - Timesamp)/9*1e-6;
+	else
+		dt = (float)(0xFFFFFF - Timesamp + Last_Timesamp)/9*1e-6;
+
+	if(dt<0.0||dt==0) dt = 0.0015f;
+	else if(dt>0.005f)
+	{
+		Last_y = x;
+		Last_Timesamp = Timesamp;
+		return x;
+	}
+	float alpha = Tf / (Tf + dt);
+	float y = alpha * Last_y + (1.0f - alpha) * x;
+	
+	Last_y = y;
+	Last_Timesamp = Timesamp;
+
+	
+	return y;
+}
+