add RSSI_DBM

dronecan/sensors/rc/1140.RCInput.uavcan

@@ -7,15 +7,17 @@
 #     RSSI >= -50 dB: 255
 #     RSSI > -120 dB and RSSI < -50 dBm: 254 / 70 * (RSSI + 120) but not smaller than 1
 #     RSSI <= -120 dB: 1
-# - STATUS_QUALITY_LQ: The quality field is valid and represents LQ in percent, 0 is no signal, 100 is 100% link quality. 
+# - STATUS_QUALITY_LQ: The quality field is valid and represents LQ in percent, 0 is no signal, 100 is 100% link quality
+# - STATUS_QUALITY_RSSI_DBM: The quality field is valid and represents RSSI in inverted dBm, 0 is no signal, 1 = -1 dBm, 255 = -255 dBm
 # - STATUS_QUALITY_SNR: The quality field is valid and represents SNR in device dependent units, value is shifted by 128 to allow
-#   representing positive and negative values: 128 = 0, 255 = +127, 1 = -127, 0 is no signal.
+#   representing positive and negative values: 128 = 0, 255 = +127, 1 = -127, 0 is no signal
 # Only one of these flags can be set at any time.
 
 uint8 STATUS_QUALITY_VALID = 1 # quality field is valid and represents RSSI in scaled uints, 0 is no signal, 255 is "full" signal
 uint8 STATUS_FAILSAFE = 2 # receiver has lost contact with transmitter
 uint8 STATUS_QUALITY_LQ = 4 # quality field is valid and represents LQ in percent, 0 is no signal, 100 is 100% link quality
-uint8 STATUS_QUALITY_SNR = 8 # quality field is valid and represents SNR in device dependent units, shifted by 128
+uint8 STATUS_QUALITY_RSSI_DBM = 8 # rssi in inverted dBm, 0 is no signal, 1 = -1 dBm, 255 = -255 dBm
+uint8 STATUS_QUALITY_SNR = 16 # quality field is valid and represents SNR in device dependent units, shifted by 128
 
 uint16 status      # bitmask of status bits, enumerated above with STATUS_*