Added RSSI offset to complement RSSI scaling.

src/main/interface/settings.c

@@ -520,6 +520,7 @@ const clivalue_t valueTable[] = {
     { "rssi_channel",               VAR_INT8   | MASTER_VALUE, .config.minmax = { 0, MAX_SUPPORTED_RC_CHANNEL_COUNT }, PG_RX_CONFIG, offsetof(rxConfig_t, rssi_channel) },
     { "rssi_src_frame_errors",      VAR_INT8   | MASTER_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_OFF_ON }, PG_RX_CONFIG, offsetof(rxConfig_t, rssi_src_frame_errors) },
     { "rssi_scale",                 VAR_UINT8  | MASTER_VALUE, .config.minmax = { RSSI_SCALE_MIN, RSSI_SCALE_MAX }, PG_RX_CONFIG, offsetof(rxConfig_t, rssi_scale) },
+    { "rssi_offset",                VAR_INT8   | MASTER_VALUE, .config.minmax = { -100, 100 }, PG_RX_CONFIG, offsetof(rxConfig_t, rssi_offset) },
     { "rssi_invert",                VAR_INT8   | MASTER_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_OFF_ON }, PG_RX_CONFIG, offsetof(rxConfig_t, rssi_invert) },
     { "rc_interp",                  VAR_UINT8  | MASTER_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_RC_INTERPOLATION }, PG_RX_CONFIG, offsetof(rxConfig_t, rcInterpolation) },
     { "rc_interp_ch",               VAR_UINT8  | MASTER_VALUE | MODE_LOOKUP, .config.lookup = { TABLE_RC_INTERPOLATION_CHANNELS }, PG_RX_CONFIG, offsetof(rxConfig_t, rcInterpolationChannels) },

src/main/pg/rx.c

@@ -52,6 +52,7 @@ void pgResetFn_rxConfig(rxConfig_t *rxConfig)
         .rssi_src_frame_errors = false,
         .rssi_channel = 0,
         .rssi_scale = RSSI_SCALE_DEFAULT,
+        .rssi_offset = 0,
         .rssi_invert = 0,
         .rcInterpolation = RC_SMOOTHING_AUTO,
         .rcInterpolationChannels = 0,

src/main/pg/rx.h

@@ -49,6 +49,7 @@ typedef struct rxConfig_s {
     uint16_t rx_max_usec;
     uint8_t max_aux_channel;
     uint8_t rssi_src_frame_errors;          // true to use frame drop flags in the rx protocol
+    int8_t rssi_offset;                     // offset applied to the RSSI value before it is returned
 } rxConfig_t;
 
 PG_DECLARE(rxConfig_t, rxConfig);

src/main/rx/rx.c

@@ -78,6 +78,7 @@ static timeUs_t lastMspRssiUpdateUs = 0;
 #define MSP_RSSI_TIMEOUT_US 1500000   // 1.5 sec
 
 #define RSSI_ADC_DIVISOR (4096 / 1024)
+#define RSSI_OFFSET_SCALING (1024 / 100.0f)
 
 rssiSource_e rssiSource;
 
@@ -680,7 +681,7 @@ void updateRSSI(timeUs_t currentTimeUs)
 
 uint16_t getRssi(void)
 {
-    return (rxConfig()->rssi_scale / 100.0f) * rssi;
+    return ((rxConfig()->rssi_scale / 100.0f) * rssi) + (rxConfig()->rssi_offset * RSSI_OFFSET_SCALING);
 }
 
 uint8_t getRssiPercent(void)