diff --git a/main.c b/main.c
index d217bf7..e06860d 100644
--- a/main.c
+++ b/main.c
@@ -980,6 +980,14 @@ bool sweep(bool break_on_operation)
 }
 #endif
 
+void set_sweep_points(uint16_t points){
+  if (points == sweep_points || points > POINTS_COUNT)
+    return;
+
+  sweep_points = points;
+  update_frequencies();
+}
+
 VNA_SHELL_FUNCTION(cmd_scan)
 {
   uint32_t start, stop;
@@ -2695,10 +2703,7 @@ int main(void)
   dacStart(&DACD2, &dac1cfg1);
 #endif
   setupSA();
-  sweep_points = POINTS_COUNT;
-/* initial frequencies */
-  update_frequencies();
-
+  set_sweep_points(POINTS_COUNT);
 
 #ifdef __VNA__
 /*
diff --git a/nanovna.h b/nanovna.h
index 9cb4150..281a0e1 100644
--- a/nanovna.h
+++ b/nanovna.h
@@ -123,6 +123,7 @@ enum stimulus_type {
   ST_START=0, ST_STOP, ST_CENTER, ST_SPAN, ST_CW
 };
 
+void set_sweep_points(uint16_t points);
 void update_frequencies(void);
 void set_sweep_frequency(int type, uint32_t frequency);
 uint32_t get_sweep_frequency(int type);