diff --git a/main.c b/main.c
index 3e0b70a..77292ef 100644
--- a/main.c
+++ b/main.c
@@ -76,10 +76,12 @@ static THD_FUNCTION(Thread1, arg)
         __WFI();
       }
 
+      chMtxLock(&mutex);
+      ui_process();
+      chMtxUnlock(&mutex);
+
       if (sweep_enabled) {
         chMtxLock(&mutex);
-        ui_process();
-
         if (vbat != -1) {
           adc_stop(ADC1);
           vbat = adc_vbat_read(ADC1);
@@ -759,9 +761,10 @@ void
 set_frequencies(uint32_t start, uint32_t stop, int16_t points)
 {
   int i;
-  uint32_t span = (stop - start) / 1000; /* prevents overflow because of maximum of int32_t(2.147e+9) */  
+  float span = stop - start;
   for (i = 0; i < points; i++)
-    frequencies[i] = start + span * i / (points - 1) * 1000;
+    frequencies[i] = start + i * span / (float)(points - 1);
+  // disable at out of sweep range
   for (; i < sweep_points; i++)
     frequencies[i] = 0;
 }
@@ -820,6 +823,7 @@ void
 set_sweep_frequency(int type, float frequency)
 {
   int32_t freq = frequency;
+  int cal_applied = cal_status & CALSTAT_APPLY;
   switch (type) {
   case ST_START:
     freq_mode_startstop();
@@ -899,7 +903,7 @@ set_sweep_frequency(int type, float frequency)
     break;
   }
 
-  if (cal_auto_interpolate && (cal_status & CALSTAT_APPLY))
+  if (cal_auto_interpolate && cal_applied)
     cal_interpolate(lastsaveid);
 }