add freq center/span

main.c

@@ -453,35 +453,82 @@ void
 update_frequencies(void)
 {
   int i;
-  int32_t span = (freq_stop - freq_start)/100;
+  int32_t span;
+  int32_t start;
+  if (freq_stop > 0) {
+    start = freq_start;
+    span = (freq_stop - freq_start)/100;
+  } else {
+    span = -freq_stop / 100;
+    start = freq_start - span/2;
+  }
+
   for (i = 0; i < sweep_points; i++)
-    frequencies[i] = freq_start + span * i / (sweep_points - 1) * 100;
+    frequencies[i] = start + span * i / (sweep_points - 1) * 100;
 
   // set grid layout
   set_sweep(freq_start, freq_stop);
 }
 
+
+void
+freq_mode_startstop(void)
+{
+  if (freq_stop <= 0) {
+    int center = freq_start;
+    int span = -freq_stop;
+    freq_start = center - span/2;
+    freq_stop = center + span/2;
+  }
+}
+
+void
+freq_mode_centerspan(void)
+{
+  if (freq_stop > 0) {
+    int start = freq_start;
+    int stop = freq_stop;
+    freq_start = (start + stop)/2; // center
+    freq_stop = -(stop - start); // span
+  }
+}
+
+
 void
 set_sweep_frequency(int type, int frequency)
 {
   switch (type) {
   case ST_START:
+    ensure_edit_config();
+    freq_mode_startstop();
     if (freq_start != frequency) {
-      ensure_edit_config();
       freq_start = frequency;
       update_frequencies();
     }
     break;
   case ST_STOP:
-    if (freq_start != frequency) {
-      ensure_edit_config();
+    ensure_edit_config();
+    freq_mode_startstop();
+    if (freq_stop != frequency) {
       freq_stop = frequency;
       update_frequencies();
     }
     break;
   case ST_CENTER:
+    ensure_edit_config();
+    freq_mode_centerspan();
+    if (freq_start != frequency) {
+      freq_start = frequency;
+      update_frequencies();
+    }
     break;
   case ST_SPAN:
+    ensure_edit_config();
+    freq_mode_centerspan();
+    if (freq_stop != -frequency) {
+      freq_stop = -frequency;
+      update_frequencies();
+    }
     break;
   }
 }
@@ -495,35 +542,34 @@ static void cmd_sweep(BaseSequentialStream *chp, int argc, char *argv[])
     chprintf(chp, "usage: sweep {start(Hz)} [stop] [points]\r\n");
     return;
   }
-  if (argc >= 1) {
-    ensure_edit_config();
-    int32_t x = atoi(argv[0]);
-    if (x < 300000) {
-      chprintf(chp, "bad parameter\r\n");
-      return;
-    }
-    freq_start = x;
-  }
   if (argc >= 2) {
-    int32_t x = atoi(argv[1]);
-    if (x < 300000 || x <= freq_start) {
-      chprintf(chp, "bad parameter\r\n");
+    if (strcmp(argv[0], "start") == 0) {
+      int32_t value = atoi(argv[1]);
+      set_sweep_frequency(ST_START, value);
       return;
-    }
-    freq_stop = x;
-  }
-#if 0
-  if (argc >= 3) {
-    int32_t x = atoi(argv[2]);
-    if (x < 1 || x > 1601) {
-      chprintf(chp, "bad parameter\r\n");
+    } else if (strcmp(argv[0], "stop") == 0) {
+      int32_t value = atoi(argv[1]);
+      set_sweep_frequency(ST_STOP, value);
+      return;
+    } else if (strcmp(argv[0], "center") == 0) {
+      int32_t value = atoi(argv[1]);
+      set_sweep_frequency(ST_CENTER, value);
+      return;
+    } else if (strcmp(argv[0], "span") == 0) {
+      int32_t value = atoi(argv[1]);
+      set_sweep_frequency(ST_SPAN, value);
       return;
     }
-    sweep_points = x;
   }
-#endif
 
-  update_frequencies();
+  if (argc >= 1) {
+    int32_t value = atoi(argv[0]);
+    set_sweep_frequency(ST_START, value);
+  }
+  if (argc >= 2) {
+    int32_t value = atoi(argv[1]);
+    set_sweep_frequency(ST_STOP, value);
+  }
 }
 
 

plot.c

@@ -74,10 +74,16 @@ void set_sweep(int32_t start, int stop)
 {
   int32_t gdigit = 100000000;
   int32_t grid;
-  fstart = start;
-  fstop = stop;
-  fspan = stop - start;
-
+  if (stop > 0) {
+    fstart = start;
+    fstop = stop;
+    fspan = stop - start;
+  } else {
+    fspan = -stop;
+    fstart = start;
+    fstop = stop;
+  }
+  
   while (gdigit > 100) {
     grid = 5 * gdigit;
     if (fspan / grid >= 4)
@@ -1234,16 +1240,31 @@ void
 draw_frequencies(void)
 {
   char buf[24];
-  chsnprintf(buf, 24, "START %d.%03d %03d MHz  ",
-             (int)(fstart / 1000000),
-             (int)((fstart / 1000) % 1000),
-             (int)(fstart % 1000));
-  ili9341_drawstring_5x7(buf, OFFSETX, 233, 0xffff, 0x0000);
-  chsnprintf(buf, 24, "STOP %d.%03d %03d MHz",
-             (int)(fstop / 1000000),
-             (int)((fstop / 1000) % 1000),
-             (int)(fstop % 1000));
-  ili9341_drawstring_5x7(buf, 205, 233, 0xffff, 0x0000);
+  if (fstop > 0) {
+    chsnprintf(buf, 24, "START %d.%03d %03d MHz  ",
+               (int)(fstart / 1000000),
+               (int)((fstart / 1000) % 1000),
+               (int)(fstart % 1000));
+    ili9341_drawstring_5x7(buf, OFFSETX, 233, 0xffff, 0x0000);
+    chsnprintf(buf, 24, "STOP %d.%03d %03d MHz",
+               (int)(fstop / 1000000),
+               (int)((fstop / 1000) % 1000),
+               (int)(fstop % 1000));
+    ili9341_drawstring_5x7(buf, 205, 233, 0xffff, 0x0000);
+  } else {
+    int fcenter = fstart;
+    int fspan = -fstop;
+    chsnprintf(buf, 24, "CENTER %d.%03d %03d MHz  ",
+               (int)(fcenter / 1000000),
+               (int)((fcenter / 1000) % 1000),
+               (int)(fcenter % 1000));
+    ili9341_drawstring_5x7(buf, OFFSETX, 233, 0xffff, 0x0000);
+    chsnprintf(buf, 24, "SPAN %d.%03d %03d MHz",
+               (int)(fspan / 1000000),
+               (int)((fspan / 1000) % 1000),
+               (int)(fspan % 1000));
+    ili9341_drawstring_5x7(buf, 205, 233, 0xffff, 0x0000);
+  }
 }
 
 void

ui.c

@@ -772,10 +772,12 @@ ui_process_keypad(void)
       } else if (c <= 9 && i < NUMINPUT_LEN)
         buf[i++] = '0' + c;
       else if (c == KP_PERIOD && i < NUMINPUT_LEN) {
+        // check period in former input
         int j;
         for (j = 0; j < i && buf[j] != '.'; j++)
           ;
-        if (buf[j] != '.')
+        // append period if there are no period
+        if (i == j)
           buf[i++] = '.';
       } else if (c == KP_BS) {
         if (i == 0) {