From 2dd58c8ed1bc590fb596ac9d6c4c778730bf33a9 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Wed, 28 Oct 2020 10:29:51 +1100
Subject: [PATCH] AP_RCProtocol: send null pkts for FPort2

when we have no data to send, we should send an empty packet to ensure
the receiver schedules us for data as often as possible
---
 libraries/AP_RCProtocol/AP_RCProtocol_FPort2.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/libraries/AP_RCProtocol/AP_RCProtocol_FPort2.cpp b/libraries/AP_RCProtocol/AP_RCProtocol_FPort2.cpp
index 0b3ee496db..18ca24044c 100644
--- a/libraries/AP_RCProtocol/AP_RCProtocol_FPort2.cpp
+++ b/libraries/AP_RCProtocol/AP_RCProtocol_FPort2.cpp
@@ -116,7 +116,11 @@ void AP_RCProtocol_FPort2::decode_downlink(const FPort2_Frame &frame)
      */
     if (!telem_data.available) {
         if (!AP_Frsky_Telem::get_telem_data(telem_data.frame, telem_data.appid, telem_data.data)) {
-            return;
+            // nothing to send, send a null frame. This ensures the
+            // receiver keeps requesting data from us at the full rate
+            telem_data.frame = 0x00; 
+            telem_data.appid = 0x00; 
+            telem_data.data = 0x00;
         }
         telem_data.available = true;
     }