Separate OSD warnings from OSD task and make available via MSP

Provides a properly implemented way for MSP query type OSD implementations (like DJI) to display OSD warnings. Separates the warnings generation from the OSD task and shares common code to make the text available for the OSD and/or via MSP. Eliminates the need to implement hacks and workarounds like using the `CRAFT_NAME` field to display warnings. Since the warnings logic is now separate, the OSD task does not need to be running unlike other hacks.

Adds the `MSP2_GET_OSD_WARNINGS` message formatted as follows:
```
byte  description
0     Display attributes including blink (see displayPortAttr_e in drivers/display.h)
1     Length of warning text
2-n   Warning text characters
```

make/source.mk

@@ -177,6 +177,7 @@ COMMON_SRC = \
             io/pidaudio.c \
             osd/osd.c \
             osd/osd_elements.c \
+            osd/osd_warnings.c \
             sensors/barometer.c \
             sensors/rangefinder.c \
             telemetry/telemetry.c \
@@ -355,6 +356,7 @@ SIZE_OPTIMISED_SRC := $(SIZE_OPTIMISED_SRC) \
             io/spektrum_vtx_control.c \
             osd/osd.c \
             osd/osd_elements.c \
+            osd/osd_warnings.c \
             rx/rx_bind.c
 
 # Gyro driver files that only contain initialization and configuration code - not runtime code

src/main/msp/msp.c

@@ -112,6 +112,7 @@
 
 #include "osd/osd.h"
 #include "osd/osd_elements.h"
+#include "osd/osd_warnings.h"
 
 #include "pg/beeper.h"
 #include "pg/board.h"
@@ -1211,6 +1212,28 @@ static bool mspProcessOutCommand(int16_t cmdMSP, sbuf_t *dst)
         break;
 #endif
 
+#ifdef USE_OSD
+    case MSP2_GET_OSD_WARNINGS:
+        {
+            bool isBlinking;
+            uint8_t displayAttr;
+            char warningsBuffer[OSD_FORMAT_MESSAGE_BUFFER_SIZE];
+
+            renderOsdWarning(warningsBuffer, &isBlinking, &displayAttr);
+            const uint8_t warningsLen = strlen(warningsBuffer);
+
+            if (isBlinking) {
+                displayAttr |= DISPLAYPORT_ATTR_BLINK;
+            }
+            sbufWriteU8(dst, displayAttr);  // see displayPortAttr_e
+            sbufWriteU8(dst, warningsLen);  // length byte followed by the actual characters
+            for (unsigned i = 0; i < warningsLen; i++) {
+                sbufWriteU8(dst, warningsBuffer[i]);
+            }
+            break;
+        }
+#endif
+
     case MSP_RC:
         for (int i = 0; i < rxRuntimeState.channelCount; i++) {
             sbufWriteU16(dst, rcData[i]);

src/main/msp/msp_protocol_v2_betaflight.h

@@ -23,3 +23,4 @@
 #define MSP2_SET_MOTOR_OUTPUT_REORDERING    0x3002
 #define MSP2_SEND_DSHOT_COMMAND             0x3003
 #define MSP2_GET_VTX_DEVICE_STATUS          0x3004
+#define MSP2_GET_OSD_WARNINGS               0x3005  // returns active OSD warning message text

src/main/osd/osd_elements.c

@@ -96,30 +96,26 @@
 #include "fc/core.h"
 #include "fc/rc_adjustments.h"
 #include "fc/rc_controls.h"
-#include "fc/rc_modes.h"
-#include "fc/rc.h"
 #include "fc/runtime_config.h"
 
 #include "flight/gps_rescue.h"
-#include "flight/failsafe.h"
 #include "flight/position.h"
 #include "flight/imu.h"
 #include "flight/mixer.h"
 #include "flight/pid.h"
 
-#include "io/beeper.h"
 #include "io/gps.h"
 #include "io/vtx.h"
 
 #include "osd/osd.h"
 #include "osd/osd_elements.h"
+#include "osd/osd_warnings.h"
 
 #include "pg/motor.h"
 #include "pg/stats.h"
 
 #include "rx/rx.h"
 
-#include "sensors/acceleration.h"
 #include "sensors/adcinternal.h"
 #include "sensors/barometer.h"
 #include "sensors/battery.h"
@@ -1319,278 +1315,13 @@ static void osdElementVtxChannel(osdElementParms_t *element)
 
 static void osdElementWarnings(osdElementParms_t *element)
 {
-#define OSD_WARNINGS_MAX_SIZE 12
+    bool elementBlinking = false;
-#define OSD_FORMAT_MESSAGE_BUFFER_SIZE (OSD_WARNINGS_MAX_SIZE + 1)
+    renderOsdWarning(element->buff, &elementBlinking, &element->attr);
-
+    if (elementBlinking) {
-    STATIC_ASSERT(OSD_FORMAT_MESSAGE_BUFFER_SIZE <= OSD_ELEMENT_BUFFER_LENGTH, osd_warnings_size_exceeds_buffer_size);
+        SET_BLINK(OSD_WARNINGS);
-
+    } else {
-    const batteryState_e batteryState = getBatteryState();
-    const timeUs_t currentTimeUs = micros();
-
-    static timeUs_t armingDisabledUpdateTimeUs;
-    static unsigned armingDisabledDisplayIndex;
-
         CLR_BLINK(OSD_WARNINGS);
-
-    // Cycle through the arming disabled reasons
-    if (osdWarnGetState(OSD_WARNING_ARMING_DISABLE)) {
-        if (IS_RC_MODE_ACTIVE(BOXARM) && isArmingDisabled()) {
-            const armingDisableFlags_e armSwitchOnlyFlag = 1 << (ARMING_DISABLE_FLAGS_COUNT - 1);
-            armingDisableFlags_e flags = getArmingDisableFlags();
-
-            // Remove the ARMSWITCH flag unless it's the only one
-            if ((flags & armSwitchOnlyFlag) && (flags != armSwitchOnlyFlag)) {
-                flags -= armSwitchOnlyFlag;
     }
-
-            // Rotate to the next arming disabled reason after a 0.5 second time delay
-            // or if the current flag is no longer set
-            if ((currentTimeUs - armingDisabledUpdateTimeUs > 5e5) || !(flags & (1 << armingDisabledDisplayIndex))) {
-                if (armingDisabledUpdateTimeUs == 0) {
-                    armingDisabledDisplayIndex = ARMING_DISABLE_FLAGS_COUNT - 1;
-                }
-                armingDisabledUpdateTimeUs = currentTimeUs;
-
-                do {
-                    if (++armingDisabledDisplayIndex >= ARMING_DISABLE_FLAGS_COUNT) {
-                        armingDisabledDisplayIndex = 0;
-                    }
-                } while (!(flags & (1 << armingDisabledDisplayIndex)));
-            }
-
-            tfp_sprintf(element->buff, "%s", armingDisableFlagNames[armingDisabledDisplayIndex]);
-            element->attr = DISPLAYPORT_ATTR_WARNING;
-            return;
-        } else {
-            armingDisabledUpdateTimeUs = 0;
-        }
-    }
-
-#ifdef USE_DSHOT
-    if (isTryingToArm() && !ARMING_FLAG(ARMED)) {
-        int armingDelayTime = (getLastDshotBeaconCommandTimeUs() + DSHOT_BEACON_GUARD_DELAY_US - currentTimeUs) / 1e5;
-        if (armingDelayTime < 0) {
-            armingDelayTime = 0;
-        }
-        if (armingDelayTime >= (DSHOT_BEACON_GUARD_DELAY_US / 1e5 - 5)) {
-            tfp_sprintf(element->buff, " BEACON ON"); // Display this message for the first 0.5 seconds
-        } else {
-            tfp_sprintf(element->buff, "ARM IN %d.%d", armingDelayTime / 10, armingDelayTime % 10);
-        }
-        element->attr = DISPLAYPORT_ATTR_INFO;
-        return;
-    }
-#endif // USE_DSHOT
-    if (osdWarnGetState(OSD_WARNING_FAIL_SAFE) && failsafeIsActive()) {
-        tfp_sprintf(element->buff, "FAIL SAFE");
-        element->attr = DISPLAYPORT_ATTR_CRITICAL;
-        SET_BLINK(OSD_WARNINGS);
-        return;
-    }
-
-    // Warn when in flip over after crash mode
-    if (osdWarnGetState(OSD_WARNING_CRASH_FLIP) && isFlipOverAfterCrashActive()) {
-        tfp_sprintf(element->buff, "CRASH FLIP");
-        element->attr = DISPLAYPORT_ATTR_INFO;
-        return;
-    }
-
-#ifdef USE_LAUNCH_CONTROL
-    // Warn when in launch control mode
-    if (osdWarnGetState(OSD_WARNING_LAUNCH_CONTROL) && isLaunchControlActive()) {
-#ifdef USE_ACC
-        if (sensors(SENSOR_ACC)) {
-            const int pitchAngle = constrain((attitude.raw[FD_PITCH] - accelerometerConfig()->accelerometerTrims.raw[FD_PITCH]) / 10, -90, 90);
-            tfp_sprintf(element->buff, "LAUNCH %d", pitchAngle);
-        } else
-#endif // USE_ACC
-        {
-            tfp_sprintf(element->buff, "LAUNCH");
-        }
-
-        // Blink the message if the throttle is within 10% of the launch setting
-        if ( calculateThrottlePercent() >= MAX(currentPidProfile->launchControlThrottlePercent - 10, 0)) {
-            SET_BLINK(OSD_WARNINGS);
-        }
-
-        element->attr = DISPLAYPORT_ATTR_INFO;
-        return;
-    }
-#endif // USE_LAUNCH_CONTROL
-
-    // RSSI
-    if (osdWarnGetState(OSD_WARNING_RSSI) && (getRssiPercent() < osdConfig()->rssi_alarm)) {
-        tfp_sprintf(element->buff, "RSSI LOW");
-        element->attr = DISPLAYPORT_ATTR_WARNING;
-        SET_BLINK(OSD_WARNINGS);
-        return;
-    }
-#ifdef USE_RX_RSSI_DBM
-    // rssi dbm
-    if (osdWarnGetState(OSD_WARNING_RSSI_DBM) && (getRssiDbm() < osdConfig()->rssi_dbm_alarm)) {
-        tfp_sprintf(element->buff, "RSSI DBM");
-        element->attr = DISPLAYPORT_ATTR_WARNING;
-        SET_BLINK(OSD_WARNINGS);
-        return;
-    }
-#endif // USE_RX_RSSI_DBM
-
-#ifdef USE_RX_LINK_QUALITY_INFO
-    // Link Quality
-    if (osdWarnGetState(OSD_WARNING_LINK_QUALITY) && (rxGetLinkQualityPercent() < osdConfig()->link_quality_alarm)) {
-        tfp_sprintf(element->buff, "LINK QUALITY");
-        element->attr = DISPLAYPORT_ATTR_WARNING;
-        SET_BLINK(OSD_WARNINGS);
-        return;
-    }
-#endif // USE_RX_LINK_QUALITY_INFO
-
-    if (osdWarnGetState(OSD_WARNING_BATTERY_CRITICAL) && batteryState == BATTERY_CRITICAL) {
-        tfp_sprintf(element->buff, " LAND NOW");
-        element->attr = DISPLAYPORT_ATTR_CRITICAL;
-        SET_BLINK(OSD_WARNINGS);
-        return;
-    }
-
-#ifdef USE_GPS_RESCUE
-    if (osdWarnGetState(OSD_WARNING_GPS_RESCUE_UNAVAILABLE) &&
-       ARMING_FLAG(ARMED) &&
-       gpsRescueIsConfigured() &&
-       !gpsRescueIsDisabled() &&
-       !gpsRescueIsAvailable()) {
-        tfp_sprintf(element->buff, "RESCUE N/A");
-        element->attr = DISPLAYPORT_ATTR_WARNING;
-        SET_BLINK(OSD_WARNINGS);
-        return;
-    }
-
-    if (osdWarnGetState(OSD_WARNING_GPS_RESCUE_DISABLED) &&
-       ARMING_FLAG(ARMED) &&
-       gpsRescueIsConfigured() &&
-       gpsRescueIsDisabled()) {
-
-        statistic_t *stats = osdGetStats();
-        if (cmpTimeUs(stats->armed_time, OSD_GPS_RESCUE_DISABLED_WARNING_DURATION_US) < 0) {
-            tfp_sprintf(element->buff, "RESCUE OFF");
-            element->attr = DISPLAYPORT_ATTR_WARNING;
-            SET_BLINK(OSD_WARNINGS);
-            return;
-        }
-    }
-
-#endif // USE_GPS_RESCUE
-
-    // Show warning if in HEADFREE flight mode
-    if (FLIGHT_MODE(HEADFREE_MODE)) {
-        tfp_sprintf(element->buff, "HEADFREE");
-        element->attr = DISPLAYPORT_ATTR_WARNING;
-        SET_BLINK(OSD_WARNINGS);
-        return;
-    }
-
-#ifdef USE_ADC_INTERNAL
-    const int16_t coreTemperature = getCoreTemperatureCelsius();
-    if (osdWarnGetState(OSD_WARNING_CORE_TEMPERATURE) && coreTemperature >= osdConfig()->core_temp_alarm) {
-        tfp_sprintf(element->buff, "CORE %c: %3d%c", SYM_TEMPERATURE, osdConvertTemperatureToSelectedUnit(coreTemperature), osdGetTemperatureSymbolForSelectedUnit());
-        element->attr = DISPLAYPORT_ATTR_WARNING;
-        SET_BLINK(OSD_WARNINGS);
-        return;
-    }
-#endif // USE_ADC_INTERNAL
-
-#ifdef USE_ESC_SENSOR
-    // Show warning if we lose motor output, the ESC is overheating or excessive current draw
-    if (featureIsEnabled(FEATURE_ESC_SENSOR) && osdWarnGetState(OSD_WARNING_ESC_FAIL)) {
-        char escWarningMsg[OSD_FORMAT_MESSAGE_BUFFER_SIZE];
-        unsigned pos = 0;
-
-        const char *title = "ESC";
-
-        // center justify message
-        while (pos < (OSD_WARNINGS_MAX_SIZE - (strlen(title) + getMotorCount())) / 2) {
-            escWarningMsg[pos++] = ' ';
-        }
-
-        strcpy(escWarningMsg + pos, title);
-        pos += strlen(title);
-
-        unsigned i = 0;
-        unsigned escWarningCount = 0;
-        while (i < getMotorCount() && pos < OSD_FORMAT_MESSAGE_BUFFER_SIZE - 1) {
-            escSensorData_t *escData = getEscSensorData(i);
-            const char motorNumber = '1' + i;
-            // if everything is OK just display motor number else R, T or C
-            char warnFlag = motorNumber;
-            if (ARMING_FLAG(ARMED) && osdConfig()->esc_rpm_alarm != ESC_RPM_ALARM_OFF && calcEscRpm(escData->rpm) <= osdConfig()->esc_rpm_alarm) {
-                warnFlag = 'R';
-            }
-            if (osdConfig()->esc_temp_alarm != ESC_TEMP_ALARM_OFF && escData->temperature >= osdConfig()->esc_temp_alarm) {
-                warnFlag = 'T';
-            }
-            if (ARMING_FLAG(ARMED) && osdConfig()->esc_current_alarm != ESC_CURRENT_ALARM_OFF && escData->current >= osdConfig()->esc_current_alarm) {
-                warnFlag = 'C';
-            }
-
-            escWarningMsg[pos++] = warnFlag;
-
-            if (warnFlag != motorNumber) {
-                escWarningCount++;
-            }
-
-            i++;
-        }
-
-        escWarningMsg[pos] = '\0';
-
-        if (escWarningCount > 0) {
-            tfp_sprintf(element->buff, "%s", escWarningMsg);
-            element->attr = DISPLAYPORT_ATTR_WARNING;
-            SET_BLINK(OSD_WARNINGS);
-            return;
-        }
-    }
-#endif // USE_ESC_SENSOR
-
-    if (osdWarnGetState(OSD_WARNING_BATTERY_WARNING) && batteryState == BATTERY_WARNING) {
-        tfp_sprintf(element->buff, "LOW BATTERY");
-        element->attr = DISPLAYPORT_ATTR_WARNING;
-        SET_BLINK(OSD_WARNINGS);
-        return;
-    }
-
-#ifdef USE_RC_SMOOTHING_FILTER
-    // Show warning if rc smoothing hasn't initialized the filters
-    if (osdWarnGetState(OSD_WARNING_RC_SMOOTHING) && ARMING_FLAG(ARMED) && !rcSmoothingInitializationComplete()) {
-        tfp_sprintf(element->buff, "RCSMOOTHING");
-        element->attr = DISPLAYPORT_ATTR_WARNING;
-        SET_BLINK(OSD_WARNINGS);
-        return;
-    }
-#endif // USE_RC_SMOOTHING_FILTER
-
-    // Show warning if mah consumed is over the configured limit
-    if (osdWarnGetState(OSD_WARNING_OVER_CAP) && ARMING_FLAG(ARMED) && osdConfig()->cap_alarm > 0 && getMAhDrawn() >= osdConfig()->cap_alarm) {
-        tfp_sprintf(element->buff, "OVER CAP");
-        element->attr = DISPLAYPORT_ATTR_WARNING;
-        SET_BLINK(OSD_WARNINGS);
-        return;
-    }
-
-    // Show warning if battery is not fresh
-    if (osdWarnGetState(OSD_WARNING_BATTERY_NOT_FULL) && !(ARMING_FLAG(ARMED) || ARMING_FLAG(WAS_EVER_ARMED)) && (getBatteryState() == BATTERY_OK)
-          && getBatteryAverageCellVoltage() < batteryConfig()->vbatfullcellvoltage) {
-        tfp_sprintf(element->buff, "BATT < FULL");
-        element->attr = DISPLAYPORT_ATTR_INFO;
-        return;
-    }
-
-    // Visual beeper
-    if (osdWarnGetState(OSD_WARNING_VISUAL_BEEPER) && osdGetVisualBeeperState()) {
-        tfp_sprintf(element->buff, "  * * * *");
-        element->attr = DISPLAYPORT_ATTR_INFO;
-        return;
-    }
-
 }
 
 // Define the order in which the elements are drawn.

src/main/osd/osd_warnings.c

@@ -0,0 +1,339 @@
+/*
+ * This file is part of Cleanflight and Betaflight.
+ *
+ * Cleanflight and Betaflight are free software. You can redistribute
+ * this software and/or modify this software under the terms of the
+ * GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * Cleanflight and Betaflight are distributed in the hope that they
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software.
+ *
+ * If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <math.h>
+
+#include "platform.h"
+
+#ifdef USE_OSD
+
+#include "config/config.h"
+#include "config/feature.h"
+
+#include "common/maths.h"
+#include "common/printf.h"
+
+#include "drivers/display.h"
+#include "drivers/osd_symbols.h"
+#include "drivers/time.h"
+
+#include "fc/core.h"
+#include "fc/rc.h"
+#include "fc/rc_modes.h"
+#include "fc/runtime_config.h"
+
+#include "flight/failsafe.h"
+#include "flight/gps_rescue.h"
+#include "flight/imu.h"
+#include "flight/mixer.h"
+#include "flight/pid.h"
+
+#include "io/beeper.h"
+
+#include "osd/osd.h"
+#include "osd/osd_elements.h"
+#include "osd/osd_warnings.h"
+
+#include "rx/rx.h"
+
+#include "sensors/acceleration.h"
+#include "sensors/adcinternal.h"
+#include "sensors/battery.h"
+#include "sensors/sensors.h"
+
+void renderOsdWarning(char *warningText, bool *blinking, uint8_t *displayAttr)
+{
+    const batteryState_e batteryState = getBatteryState();
+    const timeUs_t currentTimeUs = micros();
+
+    static timeUs_t armingDisabledUpdateTimeUs;
+    static unsigned armingDisabledDisplayIndex;
+
+    warningText[0] = '\0';
+    *displayAttr = DISPLAYPORT_ATTR_NONE;
+    *blinking = false;
+
+    // Cycle through the arming disabled reasons
+    if (osdWarnGetState(OSD_WARNING_ARMING_DISABLE)) {
+        if (IS_RC_MODE_ACTIVE(BOXARM) && isArmingDisabled()) {
+            const armingDisableFlags_e armSwitchOnlyFlag = 1 << (ARMING_DISABLE_FLAGS_COUNT - 1);
+            armingDisableFlags_e flags = getArmingDisableFlags();
+
+            // Remove the ARMSWITCH flag unless it's the only one
+            if ((flags & armSwitchOnlyFlag) && (flags != armSwitchOnlyFlag)) {
+                flags -= armSwitchOnlyFlag;
+            }
+
+            // Rotate to the next arming disabled reason after a 0.5 second time delay
+            // or if the current flag is no longer set
+            if ((currentTimeUs - armingDisabledUpdateTimeUs > 5e5) || !(flags & (1 << armingDisabledDisplayIndex))) {
+                if (armingDisabledUpdateTimeUs == 0) {
+                    armingDisabledDisplayIndex = ARMING_DISABLE_FLAGS_COUNT - 1;
+                }
+                armingDisabledUpdateTimeUs = currentTimeUs;
+
+                do {
+                    if (++armingDisabledDisplayIndex >= ARMING_DISABLE_FLAGS_COUNT) {
+                        armingDisabledDisplayIndex = 0;
+                    }
+                } while (!(flags & (1 << armingDisabledDisplayIndex)));
+            }
+
+            tfp_sprintf(warningText, "%s", armingDisableFlagNames[armingDisabledDisplayIndex]);
+            *displayAttr = DISPLAYPORT_ATTR_WARNING;
+            return;
+        } else {
+            armingDisabledUpdateTimeUs = 0;
+        }
+    }
+
+#ifdef USE_DSHOT
+    if (isTryingToArm() && !ARMING_FLAG(ARMED)) {
+        int armingDelayTime = (getLastDshotBeaconCommandTimeUs() + DSHOT_BEACON_GUARD_DELAY_US - currentTimeUs) / 1e5;
+        if (armingDelayTime < 0) {
+            armingDelayTime = 0;
+        }
+        if (armingDelayTime >= (DSHOT_BEACON_GUARD_DELAY_US / 1e5 - 5)) {
+            tfp_sprintf(warningText, " BEACON ON"); // Display this message for the first 0.5 seconds
+        } else {
+            tfp_sprintf(warningText, "ARM IN %d.%d", armingDelayTime / 10, armingDelayTime % 10);
+        }
+        *displayAttr = DISPLAYPORT_ATTR_INFO;
+        return;
+    }
+#endif // USE_DSHOT
+    if (osdWarnGetState(OSD_WARNING_FAIL_SAFE) && failsafeIsActive()) {
+        tfp_sprintf(warningText, "FAIL SAFE");
+        *displayAttr = DISPLAYPORT_ATTR_CRITICAL;
+        *blinking = true;;
+        return;
+    }
+
+    // Warn when in flip over after crash mode
+    if (osdWarnGetState(OSD_WARNING_CRASH_FLIP) && isFlipOverAfterCrashActive()) {
+        tfp_sprintf(warningText, "CRASH FLIP");
+        *displayAttr = DISPLAYPORT_ATTR_INFO;
+        return;
+    }
+
+#ifdef USE_LAUNCH_CONTROL
+    // Warn when in launch control mode
+    if (osdWarnGetState(OSD_WARNING_LAUNCH_CONTROL) && isLaunchControlActive()) {
+#ifdef USE_ACC
+        if (sensors(SENSOR_ACC)) {
+            const int pitchAngle = constrain((attitude.raw[FD_PITCH] - accelerometerConfig()->accelerometerTrims.raw[FD_PITCH]) / 10, -90, 90);
+            tfp_sprintf(warningText, "LAUNCH %d", pitchAngle);
+        } else
+#endif // USE_ACC
+        {
+            tfp_sprintf(warningText, "LAUNCH");
+        }
+
+        // Blink the message if the throttle is within 10% of the launch setting
+        if ( calculateThrottlePercent() >= MAX(currentPidProfile->launchControlThrottlePercent - 10, 0)) {
+            *blinking = true;;
+        }
+
+        *displayAttr = DISPLAYPORT_ATTR_INFO;
+        return;
+    }
+#endif // USE_LAUNCH_CONTROL
+
+    // RSSI
+    if (osdWarnGetState(OSD_WARNING_RSSI) && (getRssiPercent() < osdConfig()->rssi_alarm)) {
+        tfp_sprintf(warningText, "RSSI LOW");
+        *displayAttr = DISPLAYPORT_ATTR_WARNING;
+        *blinking = true;;
+        return;
+    }
+#ifdef USE_RX_RSSI_DBM
+    // rssi dbm
+    if (osdWarnGetState(OSD_WARNING_RSSI_DBM) && (getRssiDbm() < osdConfig()->rssi_dbm_alarm)) {
+        tfp_sprintf(warningText, "RSSI DBM");
+        *displayAttr = DISPLAYPORT_ATTR_WARNING;
+        *blinking = true;;
+        return;
+    }
+#endif // USE_RX_RSSI_DBM
+
+#ifdef USE_RX_LINK_QUALITY_INFO
+    // Link Quality
+    if (osdWarnGetState(OSD_WARNING_LINK_QUALITY) && (rxGetLinkQualityPercent() < osdConfig()->link_quality_alarm)) {
+        tfp_sprintf(warningText, "LINK QUALITY");
+        *displayAttr = DISPLAYPORT_ATTR_WARNING;
+        *blinking = true;;
+        return;
+    }
+#endif // USE_RX_LINK_QUALITY_INFO
+
+    if (osdWarnGetState(OSD_WARNING_BATTERY_CRITICAL) && batteryState == BATTERY_CRITICAL) {
+        tfp_sprintf(warningText, " LAND NOW");
+        *displayAttr = DISPLAYPORT_ATTR_CRITICAL;
+        *blinking = true;;
+        return;
+    }
+
+#ifdef USE_GPS_RESCUE
+    if (osdWarnGetState(OSD_WARNING_GPS_RESCUE_UNAVAILABLE) &&
+       ARMING_FLAG(ARMED) &&
+       gpsRescueIsConfigured() &&
+       !gpsRescueIsDisabled() &&
+       !gpsRescueIsAvailable()) {
+        tfp_sprintf(warningText, "RESCUE N/A");
+        *displayAttr = DISPLAYPORT_ATTR_WARNING;
+        *blinking = true;;
+        return;
+    }
+
+    if (osdWarnGetState(OSD_WARNING_GPS_RESCUE_DISABLED) &&
+       ARMING_FLAG(ARMED) &&
+       gpsRescueIsConfigured() &&
+       gpsRescueIsDisabled()) {
+
+        statistic_t *stats = osdGetStats();
+        if (cmpTimeUs(stats->armed_time, OSD_GPS_RESCUE_DISABLED_WARNING_DURATION_US) < 0) {
+            tfp_sprintf(warningText, "RESCUE OFF");
+            *displayAttr = DISPLAYPORT_ATTR_WARNING;
+            *blinking = true;;
+            return;
+        }
+    }
+
+#endif // USE_GPS_RESCUE
+
+    // Show warning if in HEADFREE flight mode
+    if (FLIGHT_MODE(HEADFREE_MODE)) {
+        tfp_sprintf(warningText, "HEADFREE");
+        *displayAttr = DISPLAYPORT_ATTR_WARNING;
+        *blinking = true;;
+        return;
+    }
+
+#ifdef USE_ADC_INTERNAL
+    const int16_t coreTemperature = getCoreTemperatureCelsius();
+    if (osdWarnGetState(OSD_WARNING_CORE_TEMPERATURE) && coreTemperature >= osdConfig()->core_temp_alarm) {
+        tfp_sprintf(warningText, "CORE %c: %3d%c", SYM_TEMPERATURE, osdConvertTemperatureToSelectedUnit(coreTemperature), osdGetTemperatureSymbolForSelectedUnit());
+        *displayAttr = DISPLAYPORT_ATTR_WARNING;
+        *blinking = true;;
+        return;
+    }
+#endif // USE_ADC_INTERNAL
+
+#ifdef USE_ESC_SENSOR
+    // Show warning if we lose motor output, the ESC is overheating or excessive current draw
+    if (featureIsEnabled(FEATURE_ESC_SENSOR) && osdWarnGetState(OSD_WARNING_ESC_FAIL)) {
+        char escWarningMsg[OSD_FORMAT_MESSAGE_BUFFER_SIZE];
+        unsigned pos = 0;
+
+        const char *title = "ESC";
+
+        // center justify message
+        while (pos < (OSD_WARNINGS_MAX_SIZE - (strlen(title) + getMotorCount())) / 2) {
+            escWarningMsg[pos++] = ' ';
+        }
+
+        strcpy(escWarningMsg + pos, title);
+        pos += strlen(title);
+
+        unsigned i = 0;
+        unsigned escWarningCount = 0;
+        while (i < getMotorCount() && pos < OSD_FORMAT_MESSAGE_BUFFER_SIZE - 1) {
+            escSensorData_t *escData = getEscSensorData(i);
+            const char motorNumber = '1' + i;
+            // if everything is OK just display motor number else R, T or C
+            char warnFlag = motorNumber;
+            if (ARMING_FLAG(ARMED) && osdConfig()->esc_rpm_alarm != ESC_RPM_ALARM_OFF && calcEscRpm(escData->rpm) <= osdConfig()->esc_rpm_alarm) {
+                warnFlag = 'R';
+            }
+            if (osdConfig()->esc_temp_alarm != ESC_TEMP_ALARM_OFF && escData->temperature >= osdConfig()->esc_temp_alarm) {
+                warnFlag = 'T';
+            }
+            if (ARMING_FLAG(ARMED) && osdConfig()->esc_current_alarm != ESC_CURRENT_ALARM_OFF && escData->current >= osdConfig()->esc_current_alarm) {
+                warnFlag = 'C';
+            }
+
+            escWarningMsg[pos++] = warnFlag;
+
+            if (warnFlag != motorNumber) {
+                escWarningCount++;
+            }
+
+            i++;
+        }
+
+        escWarningMsg[pos] = '\0';
+
+        if (escWarningCount > 0) {
+            tfp_sprintf(warningText, "%s", escWarningMsg);
+            *displayAttr = DISPLAYPORT_ATTR_WARNING;
+            *blinking = true;;
+            return;
+        }
+    }
+#endif // USE_ESC_SENSOR
+
+    if (osdWarnGetState(OSD_WARNING_BATTERY_WARNING) && batteryState == BATTERY_WARNING) {
+        tfp_sprintf(warningText, "LOW BATTERY");
+        *displayAttr = DISPLAYPORT_ATTR_WARNING;
+        *blinking = true;;
+        return;
+    }
+
+#ifdef USE_RC_SMOOTHING_FILTER
+    // Show warning if rc smoothing hasn't initialized the filters
+    if (osdWarnGetState(OSD_WARNING_RC_SMOOTHING) && ARMING_FLAG(ARMED) && !rcSmoothingInitializationComplete()) {
+        tfp_sprintf(warningText, "RCSMOOTHING");
+        *displayAttr = DISPLAYPORT_ATTR_WARNING;
+        *blinking = true;;
+        return;
+    }
+#endif // USE_RC_SMOOTHING_FILTER
+
+    // Show warning if mah consumed is over the configured limit
+    if (osdWarnGetState(OSD_WARNING_OVER_CAP) && ARMING_FLAG(ARMED) && osdConfig()->cap_alarm > 0 && getMAhDrawn() >= osdConfig()->cap_alarm) {
+        tfp_sprintf(warningText, "OVER CAP");
+        *displayAttr = DISPLAYPORT_ATTR_WARNING;
+        *blinking = true;;
+        return;
+    }
+
+    // Show warning if battery is not fresh
+    if (osdWarnGetState(OSD_WARNING_BATTERY_NOT_FULL) && !(ARMING_FLAG(ARMED) || ARMING_FLAG(WAS_EVER_ARMED)) && (getBatteryState() == BATTERY_OK)
+          && getBatteryAverageCellVoltage() < batteryConfig()->vbatfullcellvoltage) {
+        tfp_sprintf(warningText, "BATT < FULL");
+        *displayAttr = DISPLAYPORT_ATTR_INFO;
+        return;
+    }
+
+    // Visual beeper
+    if (osdWarnGetState(OSD_WARNING_VISUAL_BEEPER) && osdGetVisualBeeperState()) {
+        tfp_sprintf(warningText, "  * * * *");
+        *displayAttr = DISPLAYPORT_ATTR_INFO;
+        return;
+    }
+
+}
+
+#endif // USE_OSD

src/main/osd/osd_warnings.h

@@ -0,0 +1,28 @@
+/*
+ * This file is part of Cleanflight and Betaflight.
+ *
+ * Cleanflight and Betaflight are free software. You can redistribute
+ * this software and/or modify this software under the terms of the
+ * GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * Cleanflight and Betaflight are distributed in the hope that they
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software.
+ *
+ * If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#define OSD_WARNINGS_MAX_SIZE 12
+#define OSD_FORMAT_MESSAGE_BUFFER_SIZE (OSD_WARNINGS_MAX_SIZE + 1)
+
+STATIC_ASSERT(OSD_FORMAT_MESSAGE_BUFFER_SIZE <= OSD_ELEMENT_BUFFER_LENGTH, osd_warnings_size_exceeds_buffer_size);
+
+void renderOsdWarning(char *warningText, bool *blinking, uint8_t *displayAttr);

src/test/Makefile

@@ -186,6 +186,7 @@ motor_output_unittest_SRC := \
 osd_unittest_SRC := \
 		$(USER_DIR)/osd/osd.c \
 		$(USER_DIR)/osd/osd_elements.c \
+		$(USER_DIR)/osd/osd_warnings.c \
 		$(USER_DIR)/common/typeconversion.c \
 		$(USER_DIR)/drivers/display.c \
 		$(USER_DIR)/common/maths.c \
@@ -202,6 +203,7 @@ osd_unittest_DEFINES := \
 link_quality_unittest_SRC := \
 		$(USER_DIR)/osd/osd.c \
 		$(USER_DIR)/osd/osd_elements.c \
+		$(USER_DIR)/osd/osd_warnings.c \
 		$(USER_DIR)/common/typeconversion.c \
 		$(USER_DIR)/drivers/display.c \
 		$(USER_DIR)/drivers/serial.c \

src/test/unit/link_quality_unittest.cc

@@ -27,26 +27,27 @@ extern "C" {
     #include "blackbox/blackbox.h"
     #include "blackbox/blackbox_io.h"
 
-    #include "common/time.h"
     #include "common/crc.h"
-    #include "common/utils.h"
     #include "common/printf.h"
     #include "common/streambuf.h"
+    #include "common/time.h"
+    #include "common/utils.h"
+
+    #include "config/config.h"
 
     #include "drivers/osd_symbols.h"
     #include "drivers/persistent.h"
     #include "drivers/serial.h"
     #include "drivers/system.h"
 
-    #include "config/config.h"
     #include "fc/core.h"
     #include "fc/rc_controls.h"
     #include "fc/rc_modes.h"
     #include "fc/runtime_config.h"
 
+    #include "flight/imu.h"
     #include "flight/mixer.h"
     #include "flight/pid.h"
-    #include "flight/imu.h"
 
     #include "io/beeper.h"
     #include "io/gps.h"
@@ -54,6 +55,7 @@ extern "C" {
 
     #include "osd/osd.h"
     #include "osd/osd_elements.h"
+    #include "osd/osd_warnings.h"
 
     #include "pg/pg.h"
     #include "pg/pg_ids.h"

src/test/unit/osd_unittest.cc

@@ -28,39 +28,40 @@ extern "C" {
     #include "blackbox/blackbox.h"
     #include "blackbox/blackbox_io.h"
 
-    #include "config/feature.h"
-
-    #include "pg/pg.h"
-    #include "pg/pg_ids.h"
-    #include "pg/rx.h"
-
     #include "common/time.h"
 
+    #include "config/config.h"
+    #include "config/feature.h"
+
     #include "drivers/osd_symbols.h"
     #include "drivers/persistent.h"
     #include "drivers/serial.h"
 
-    #include "config/config.h"
     #include "fc/core.h"
     #include "fc/rc_controls.h"
     #include "fc/rc_modes.h"
     #include "fc/runtime_config.h"
 
     #include "flight/gps_rescue.h"
-    #include "flight/pid.h"
     #include "flight/imu.h"
+    #include "flight/mixer.h"
+    #include "flight/pid.h"
 
     #include "io/beeper.h"
     #include "io/gps.h"
 
     #include "osd/osd.h"
     #include "osd/osd_elements.h"
+    #include "osd/osd_warnings.h"
+
+    #include "pg/pg.h"
+    #include "pg/pg_ids.h"
+    #include "pg/rx.h"
 
     #include "sensors/acceleration.h"
     #include "sensors/battery.h"
 
     #include "rx/rx.h"
-    #include "flight/mixer.h"
 
     void osdRefresh(timeUs_t currentTimeUs);
     void osdFormatTime(char * buff, osd_timer_precision_e precision, timeUs_t time);