Update libraries/AP_HAL_ChibiOS/hwdef/BlitzH743Pro/README.md

Co-authored-by: Henry Wurzburg <[email protected]>

libraries/AP_HAL_ChibiOS/hwdef/BlitzH743Pro/README.md

@@ -78,6 +78,11 @@ Video Power Control
 ================
 
 The 12V video power can be turned off/on  using GPIO 81 which is already assigned by default to RELAY2.  This relay can be controlled either from the GCS or using a transmitter channel (See :ref:`common-auxiliary-functions`)
+RSSI
+====
+
+Analog RSSI pin is "4"
+
 ## Battery Monitoring
 
 The board has a builtin voltage sensor and a current sensor input tied to its 4 in 1 ESC current sensor. The voltage sensor can handle up to 6S