add systick ； issue -- i2c transfer unstable

3rd/lowpass_filter.c

@@ -1,42 +1,48 @@
 
 #include <stdint.h>
-
+#include <ti_msp_dl_config.h>
 
 float y = 0;
 float Lowpassfilter_sim(float x)
 {
-	float out = 0.9*x + 0.1*y;
-	y = x;
-	return out;
+    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;
+    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;
+    uint32_t Timesamp = DL_SYSTICK_getValue();
+    if(Timesamp < Last_Timesamp)
+    {
+        dt = (float)(Last_Timesamp - Timesamp) / 32 * 1e-6;
+    }
+    else
+    {
+        dt = (float)(0xFFFFFF - Timesamp + Last_Timesamp) / 32 * 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;
+    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;
 
-	
-	return y;
+    Last_y = y;
+    Last_Timesamp = Timesamp;
+
+
+    return y;
 }