Simplified the OSD blink frequency calculation.

src/main/osd/osd.c

@@ -250,7 +250,7 @@ void osdAnalyzeActiveElements(void)
     osdDrawActiveElementsBackground(osdDisplayPort);
 }
 
-static void osdDrawElements(timeUs_t currentTimeUs)
+static void osdDrawElements(void)
 {
     // Hide OSD when OSDSW mode is active
     if (IS_RC_MODE_ACTIVE(BOXOSD)) {
@@ -268,7 +268,7 @@ static void osdDrawElements(timeUs_t currentTimeUs)
         displayClearScreen(osdDisplayPort);
     }
 
-    osdDrawActiveElements(osdDisplayPort, currentTimeUs);
+    osdDrawActiveElements(osdDisplayPort);
 }
 
 const uint16_t osdTimerDefault[OSD_TIMER_COUNT] = {
@@ -982,7 +982,7 @@ STATIC_UNIT_TESTED void osdRefresh(timeUs_t currentTimeUs)
 #endif
     {
         osdUpdateAlarms();
-        osdDrawElements(currentTimeUs);
+        osdDrawElements();
         displayHeartbeat(osdDisplayPort);
     }
     displayCommitTransaction(osdDisplayPort);
@@ -1024,13 +1024,7 @@ void osdUpdate(timeUs_t currentTimeUs)
 #endif
 
     // redraw values in buffer
-#ifdef USE_MAX7456
-#define DRAW_FREQ_DENOM 5
-#else
-#define DRAW_FREQ_DENOM 10 // MWOSD @ 115200 baud (
-#endif
-
-    if (counter % DRAW_FREQ_DENOM == 0) {
+    if (counter % OSD_DRAW_FREQ_DENOM == 0) {
         osdRefresh(currentTimeUs);
         showVisualBeeper = false;
     } else {
@@ -1039,7 +1033,7 @@ void osdUpdate(timeUs_t currentTimeUs)
         // For the MSP displayPort device only do the drawScreen once per
         // logical OSD cycle as there is no output buffering needing to be flushed.
         if (osdDisplayPortDeviceType == OSD_DISPLAYPORT_DEVICE_MSP) {
-            doDrawScreen = (counter % DRAW_FREQ_DENOM == 1);
+            doDrawScreen = (counter % OSD_DRAW_FREQ_DENOM == 1);
         }
 #endif
         // Redraw a portion of the chars per idle to spread out the load and SPI bus utilization

src/main/osd/osd.h

@@ -84,6 +84,13 @@ extern const char * const osdTimerSourceNames[OSD_NUM_TIMER_TYPES];
 #define OSD_TIMER_PRECISION(timer)  ((timer >> 4) & 0x0F)
 #define OSD_TIMER_ALARM(timer)      ((timer >> 8) & 0xFF)
 
+#ifdef USE_MAX7456
+#define OSD_DRAW_FREQ_DENOM 5
+#else
+// MWOSD @ 115200 baud
+#define OSD_DRAW_FREQ_DENOM 10
+#endif
+
 // NB: to ensure backwards compatibility, new enum values must be appended at the end but before the OSD_XXXX_COUNT entry.
 
 // *** IMPORTANT ***

src/main/osd/osd_elements.c

@@ -1877,9 +1877,11 @@ static void osdDrawSingleElementBackground(displayPort_t *osdDisplayPort, uint8_
     }
 }
 
-void osdDrawActiveElements(displayPort_t *osdDisplayPort, timeUs_t currentTimeUs)
+#define OSD_BLINK_FREQUENCY_HZ 2.5f
+
+void osdDrawActiveElements(displayPort_t *osdDisplayPort)
 {
-    static int blinkLoopCounter = 0;
+    static unsigned blinkLoopCounter = 0;
 
 #ifdef USE_GPS
     static bool lastGpsSensorState;
@@ -1892,15 +1894,10 @@ void osdDrawActiveElements(displayPort_t *osdDisplayPort, timeUs_t currentTimeUs
     }
 #endif // USE_GPS
 
-    if (osdConfig()->task_frequency == OSD_TASK_FREQUENCY_DEFAULT) {
-        // synchronize the blinking with the OSD task loop
-        if (++blinkLoopCounter >= 2) {
-            blinkState = !blinkState;
-            blinkLoopCounter = 0;
-        }
-    } else {
-        // OSD task frequency is non-standard so revert to time-based blink intervals
-        blinkState = (currentTimeUs / 200000) % 2;
+    // synchronize the blinking with the OSD task loop
+    if (++blinkLoopCounter >= lrintf(osdConfig()->task_frequency / OSD_DRAW_FREQ_DENOM / (OSD_BLINK_FREQUENCY_HZ * 2))) {
+        blinkState = !blinkState;
+        blinkLoopCounter = 0;
     }
 
     for (unsigned i = 0; i < activeOsdElementCount; i++) {

src/main/osd/osd_elements.h

@@ -47,7 +47,7 @@ int32_t osdGetSpeedToSelectedUnit(int32_t value);
 char osdGetSpeedToSelectedUnitSymbol(void);
 char osdGetTemperatureSymbolForSelectedUnit(void);
 void osdAddActiveElements(void);
-void osdDrawActiveElements(displayPort_t *osdDisplayPort, timeUs_t currentTimeUs);
+void osdDrawActiveElements(displayPort_t *osdDisplayPort);
 void osdDrawActiveElementsBackground(displayPort_t *osdDisplayPort);
 void osdElementsInit(bool backgroundLayerFlag);
 void osdResetAlarms(void);

src/test/unit/osd_unittest.cc

@@ -673,7 +673,7 @@ TEST_F(OsdTest, TestAlarms)
         printf("%d\n", i);
         displayPortTestPrint();
 #endif
-        if (i % 2 == 0) {
+        if (i % 2 == 1) {
             displayPortTestBufferSubstring(8,  1, "%c12", SYM_RSSI);
             displayPortTestBufferSubstring(12, 1, "%c13.5%c", SYM_MAIN_BATT, SYM_VOLT);
             displayPortTestBufferSubstring(1,  1, "%c02:", SYM_FLY_M); // only test the minute part of the timer
@@ -1044,6 +1044,7 @@ TEST_F(OsdTest, TestElementWarningsBattery)
     // when
     displayClearScreen(&testDisplayPort);
     osdRefresh(simulationTime);
+    osdRefresh(simulationTime);
 
     // then
     displayPortTestBufferSubstring(9, 10, " LAND NOW   ");