smartaudio: autmatically convert dbm values to labels

src/driver/vtx/sa.c

@@ -46,15 +46,11 @@ extern uint32_t vtx_last_request;
 extern uint8_t vtx_payload[32];
 extern uint8_t vtx_payload_offset;
 
-const uint8_t default_dac_power_levels[VTX_POWER_LEVEL_MAX] = {
+const uint8_t default_dac_power_levels[4] = {
     7,
     16,
     25,
     40,
-    40,
-    40,
-    40,
-    40,
 };
 
 static void serial_smart_audio_reconfigure() {
@@ -125,13 +121,18 @@ static uint8_t serial_smart_audio_parse_packet(uint8_t cmd, uint8_t *payload, ui
     if (cmd == SA_CMD_GET_SETTINGS_V21) {
       smart_audio_settings.power = payload[5];
 
-      const uint8_t count = max(payload[6], VTX_POWER_LEVEL_MAX);
+      smart_audio_settings.level_count = min(payload[6], VTX_POWER_LEVEL_MAX);
 
-      for (uint8_t i = 0; i < count; i++) {
-        smart_audio_settings.dac_power_levels[i] = payload[7 + i];
+      // SmartAudio seems to report buf[8] + 1 power levels, but one of them is zero.
+      // zero is indeed a valid power level to set the vtx to, but it activates pit mode.
+      // crucially, after sending 0 dbm, the vtx does NOT report its power level to be 0 dbm.
+      // instead, it reports whatever value was set previously and it reports to be in pit mode.
+      for (uint8_t i = 0; i < smart_audio_settings.level_count; i++) {
+        smart_audio_settings.dac_power_levels[i] = payload[7 + i + 1]; //+ 1 to skip the first power level, as mentioned above
       }
     } else {
-      for (uint8_t i = 0; i < VTX_POWER_LEVEL_MAX; i++) {
+      smart_audio_settings.level_count = 4;
+      for (uint8_t i = 0; i < smart_audio_settings.level_count; i++) {
         smart_audio_settings.dac_power_levels[i] = default_dac_power_levels[i];
       }
     }

src/driver/vtx/sa.h

@@ -28,6 +28,7 @@ typedef struct {
   uint8_t power;
   uint8_t mode;
   uint16_t frequency;
+  uint8_t level_count;
   uint16_t dac_power_levels[8];
 } smart_audio_settings_t;
 

src/io/msp.c

@@ -466,7 +466,7 @@ static void msp_process_serial_cmd(msp_t *msp, msp_magic_t magic, uint16_t cmd,
 
   case MSP_VTXTABLE_POWERLEVEL: {
     const uint8_t level = payload[0];
-    if (level <= 0 || level > VTX_POWER_LEVEL_MAX) {
+    if (level <= 0 || level > vtx_actual.power_table.levels) {
       msp_send_error(msp, magic, cmd);
       break;
     }

src/io/vtx.c

@@ -400,7 +400,7 @@ void vtx_set(vtx_settings_t *vtx) {
   if (vtx_settings.pit_mode != VTX_PIT_MODE_NO_SUPPORT)
     vtx_settings.pit_mode = vtx->pit_mode;
 
-  vtx_settings.power_level = vtx->power_level < VTX_POWER_LEVEL_MAX ? vtx->power_level : (VTX_POWER_LEVEL_MAX - 1);
+  vtx_settings.power_level = vtx->power_level < vtx_settings.power_table.levels ? vtx->power_level : (vtx_settings.power_table.levels - 1);
 
   vtx_settings.band = vtx->band < VTX_BAND_MAX ? vtx->band : 0;
   vtx_settings.channel = vtx->channel < VTX_CHANNEL_MAX ? vtx->channel : 0;

src/io/vtx_smartaudio.c

@@ -1,5 +1,6 @@
 #include "vtx.h"
 
+#include <math.h>
 #include <string.h>
 
 #include "driver/serial.h"
@@ -17,17 +18,36 @@ extern smart_audio_settings_t smart_audio_settings;
 
 static bool smart_audio_needs_update = false;
 
-static const char smart_audio_power_level_labels[VTX_POWER_LEVEL_MAX][VTX_POWER_LABEL_LEN] = {
+static const char smart_audio_power_level_labels[4][VTX_POWER_LABEL_LEN] = {
     "25   ",
-    "100  ",
     "200  ",
-    "300  ",
-    "400  ",
-    "     ",
-    "     ",
-    "     ",
+    "500  ",
+    "800  ",
 };
 
+static uint32_t smart_audio_dbi_to_mw(uint16_t dbi) {
+  uint16_t mw = (uint16_t)powf(10.0f, dbi / 10.0f);
+  if (dbi > 14) {
+    // For powers greater than 25mW round up to a multiple of 50 to match expectations
+    mw = 50 * ((mw + 25) / 50);
+  }
+  return mw;
+}
+
+static char *i2a(char *ptr, uint32_t val) {
+  const uint32_t div = val / 10;
+  if (div > 0)
+    ptr = i2a(ptr, div);
+  *ptr = '0' + (val % 10);
+  return ptr + 1;
+}
+
+static void smart_audio_write_mw(char *buf, uint32_t val) {
+  char *ptr = i2a(buf, val);
+  while (ptr != (buf + VTX_POWER_LABEL_LEN))
+    *ptr++ = ' ';
+}
+
 vtx_detect_status_t vtx_smart_audio_update(vtx_settings_t *actual) {
   if (smart_audio_settings.version == 0 && vtx_connect_tries > SMART_AUDIO_DETECT_TRIES) {
     return VTX_DETECT_ERROR;
@@ -55,9 +75,15 @@ vtx_detect_status_t vtx_smart_audio_update(vtx_settings_t *actual) {
       actual->channel = channel_index % VTX_CHANNEL_MAX;
     }
 
-    actual->power_table.levels = VTX_POWER_LEVEL_MAX;
+    actual->power_table.levels = smart_audio_settings.level_count;
     memcpy(actual->power_table.values, smart_audio_settings.dac_power_levels, sizeof(smart_audio_settings.dac_power_levels));
-    memcpy(actual->power_table.labels, smart_audio_power_level_labels, sizeof(smart_audio_power_level_labels));
+    if (smart_audio_settings.version == 3) {
+      for (uint32_t i = 0; i < smart_audio_settings.level_count; i++) {
+        smart_audio_write_mw(actual->power_table.labels[i], smart_audio_dbi_to_mw(smart_audio_settings.dac_power_levels[i]));
+      }
+    } else {
+      memcpy(actual->power_table.labels, smart_audio_power_level_labels, sizeof(smart_audio_power_level_labels));
+    }
 
     if (smart_audio_settings.version == 2) {
       actual->power_level = min(smart_audio_settings.power, VTX_POWER_LEVEL_MAX - 1);

src/io/vtx_tramp.c

@@ -21,6 +21,9 @@ static const uint16_t tramp_power_level_values[VTX_POWER_LEVEL_MAX] = {
     200,
     300,
     400,
+    0,
+    0,
+    0,
 };
 
 static const char tramp_power_level_labels[VTX_POWER_LEVEL_MAX][VTX_POWER_LABEL_LEN] = {

src/osd/render.c

@@ -931,7 +931,7 @@ void osd_display() {
       static char power_level_labels_terminated[VTX_POWER_LEVEL_MAX][VTX_POWER_LABEL_LEN + 1];
       if (!vtx_buffer_populated) {
         vtx_settings_copy = vtx_settings;
-        for (uint8_t i = 0; i < VTX_POWER_LEVEL_MAX; i++) {
+        for (uint8_t i = 0; i < vtx_settings.power_table.levels; i++) {
           memcpy(power_level_labels_terminated[i], vtx_settings.power_table.labels[i], VTX_POWER_LABEL_LEN);
           power_level_labels_terminated[i][VTX_POWER_LABEL_LEN] = 0;
           power_level_labels[i] = power_level_labels_terminated[i];
@@ -947,7 +947,7 @@ void osd_display() {
 
       const char *channel_labels[] = {"1", "2", "3", "4", "5", "6", "7", "8"};
       osd_menu_select_enum_adjust(4, 5, "CHANNEL", 20, &vtx_settings_copy.channel, channel_labels, VTX_CHANNEL_1, VTX_CHANNEL_8);
-      osd_menu_select_enum_adjust(4, 6, "POWER LEVEL", 20, &vtx_settings_copy.power_level, power_level_labels, VTX_POWER_LEVEL_1, VTX_POWER_LEVEL_MAX - 1);
+      osd_menu_select_enum_adjust(4, 6, "POWER LEVEL", 20, &vtx_settings_copy.power_level, power_level_labels, VTX_POWER_LEVEL_1, vtx_settings.power_table.levels - 1);
 
       const char *pit_mode_labels[] = {"OFF", "ON ", "N/A"};
       osd_menu_select(4, 7, "PITMODE");