From 56b4a2bd7b61a154ed944ff567a08d934143cf25 Mon Sep 17 00:00:00 2001
From: Matthias Blankertz <matthias@blankertz.org>
Date: Sun, 14 May 2023 12:52:40 +0200
Subject: [PATCH] - Allow other scripts / inputs to control AP heading too -
 Fix failure if rp2040_hid is connected above 32767 feet

---
 FlyWithLua/rpi2040_hid.lua | 16 +++++++++++++++-
 src/main.c                 |  6 +++---
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/FlyWithLua/rpi2040_hid.lua b/FlyWithLua/rpi2040_hid.lua
index 97eb904..6587c62 100644
--- a/FlyWithLua/rpi2040_hid.lua
+++ b/FlyWithLua/rpi2040_hid.lua
@@ -130,6 +130,8 @@ else
    send_app_report(device, math.floor(ap_hdg + 0.5), build_leds(), math.floor(ap_alt + 0.5), -2, -2, status_machmode == 1)
    local prev_status_altmode = 0
    local prev_status_machmode = status_machmode
+   local prev_ap_hdg = ap_hdg
+   local prev_report_ap_hdg = 0
    function usb_app()
       local send_hdg = -1
       local send_alt = -1
@@ -157,9 +159,15 @@ else
 	 mag_hdg_int = math.floor(mag_hdg + 0.5)
 	 ap_hdg = mag_hdg_int
 	 send_hdg = mag_hdg_int
-      elseif app_report_good and app_report[1] ~= 0xffff then
+      elseif prev_ap_hdg ~= ap_hdg then
+	 send_hdg = ap_hdg
+      elseif app_report_good and app_report[1] ~= 0xffff and prev_report_ap_hdg ~= app_report[1] then
 	 ap_hdg = app_report[1]
       end
+      prev_ap_hdg = ap_hdg
+      if app_report_good and app_report[1] ~= 0xffff then
+	 prev_report_ap_hdg = app_report[1]
+      end
       -- autopilot altitude
       if button(button_offset + button_alt_sync) and not last_button(button_offset + button_alt_sync) then
 	 cur_alt_int = math.floor(cur_alt + 0.5)
@@ -213,4 +221,10 @@ else
    end
 
    do_every_frame("usb_app()")
+
+   function exit_handler()
+      send_app_report(device, -2, 0, -2, -2, -2, 0)
+   end
+
+   do_on_exit('exit_handler()')
 end
diff --git a/src/main.c b/src/main.c
index 81be171..f72f010 100644
--- a/src/main.c
+++ b/src/main.c
@@ -36,7 +36,7 @@ __attribute__((packed)) struct app_report {
         struct __attribute__((packed)) {
             int16_t hdg;
             int16_t leds;
-            int16_t alt;
+            uint16_t alt;
             int16_t vs;
             int16_t as;
         } update;
@@ -228,7 +228,7 @@ static void hid_task(void)
 
     if (start_ms % 10 == 0 && send_heading_reports) {
         struct app_report report = { .type = APP_UPDATE | mach_mode ? APP_FLAG_MACH : 0,
-                                     .update = { .hdg = -1, .alt = -1, .vs = -1, .as = -1 } };
+                                     .update = { .hdg = -1, .alt = 0xffff, .vs = -1, .as = -1 } };
         if (send_heading_reports)
             report.update.hdg = hdg;
         if (send_alt_reports)
@@ -271,7 +271,7 @@ static void app_update_report(struct app_report const *report)
         update_hdg_display();
         send_heading_reports = true;
     }
-    if (report->update.alt >= 0) {
+    if (report->update.alt != 0xffff) {
         alt = report->update.alt;
         update_alt_display();
         send_alt_reports = true;